<?xml version="1.0" encoding="US-ASCII"?>
<!-- RR Donnelley Xcelerate Taxonomy Labels Linkbase, based on XBRL 2.1  http://www.edgar-online.com/ -->
<!-- Version: 6.20.1 -->
<!-- Round: 5 -->
<!-- Creation date: 2013-05-09T18:55:51Z -->
<!-- Copyright (c) 2005-2013 R.R. Donnelley & Sons Company All Rights Reserved. -->
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xml:lang="en-US" id="id_1835722_508241_1_1">Accounts Receivable Net Current</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_lbl" xml:lang="en-US" id="id_1835722_507666_1_1">Acquired Finite Lived Intangible Assets [Line Items]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_lbl" xml:lang="en-US" id="id_1835722_502084_1_1">Acquired Finite Lived Intangible Assets Weighted Average Useful Life</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AdditionalPaidInCapital_lbl" xml:lang="en-US" id="id_1835722_514143_2_1">Additional paid-in capital</label>
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    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization" xlink:label="mrcy_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization_lbl" xml:lang="en-US" id="id_1835722_524269_3_1">Tabular disclosure of adjusted EBITDA. Adjusted EBITDA is defined as earnings from continuing operations before interest income and expense, income taxes, depreciation, amortization of acquired intangible assets, restructuring, impairment of long-lived assets, acquisition costs and other related expenses, fair value adjustments from purchase accounting and stock-based compensation costs.</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xml:lang="en-US" id="id_1835722_502541_1_1">Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xml:lang="en-US" id="id_1835722_502541_2_1">Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:</label>
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    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_AdvancedComputingSolutionsMember" xlink:label="mrcy_AdvancedComputingSolutionsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_AdvancedComputingSolutionsMember_lbl" xml:lang="en-US" id="id_1835722_601396_3_1">Advanced Computing Solutions [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_AdvancedComputingSolutionsMember_lbl" xml:lang="en-US" id="id_1835722_601396_1_1">Advanced Computing Solutions [Member]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax" xlink:label="us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AssetsAbstract_lbl" xml:lang="en-US" id="id_1835722_498468_2_1">Assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsAbstract" xlink:to="us-gaap_AssetsAbstract_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AssetsCurrent_lbl" xml:lang="en-US" id="id_1835722_513098_1_1">Assets Current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_AssetsCurrent_lbl" xml:lang="en-US" id="id_1835722_513098_6_1">Total current assets</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="us-gaap_AssetsCurrentAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xml:lang="en-US" id="id_1835722_513511_1_1">Assets Current [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xml:lang="en-US" id="id_1835722_513511_2_1">Current assets:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_AssetsCurrentAbstract_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AssetsFairValueDisclosure_lbl" xml:lang="en-US" id="id_1835722_508331_1_1">Assets Fair Value Disclosure</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AssetsFairValueDisclosure_lbl" xml:lang="en-US" id="id_1835722_508331_2_1">Fair value measurement disclosure</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsFairValueDisclosure" xlink:to="us-gaap_AssetsFairValueDisclosure_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract" xlink:label="us-gaap_AssetsFairValueDisclosureAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AssetsFairValueDisclosureAbstract_lbl" xml:lang="en-US" id="id_1835722_501016_1_1">Assets Fair Value Disclosure [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AssetsFairValueDisclosureAbstract_lbl" xml:lang="en-US" id="id_1835722_501016_2_1">Assets:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsFairValueDisclosureAbstract" xlink:to="us-gaap_AssetsFairValueDisclosureAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AwardTypeAxis_lbl" xml:lang="en-US" id="id_1835722_508454_1_1">Award Type [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AwardTypeAxis_lbl" xml:lang="en-US" id="id_1835722_508454_2_1">Award Type</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_AwardTypeAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_BacklogMember" xlink:label="mrcy_BacklogMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_BacklogMember_lbl" xml:lang="en-US" id="id_1835722_533986_3_1">Backlog [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_BacklogMember_lbl" xml:lang="en-US" id="id_1835722_533986_1_1">Backlog [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_BacklogMember_lbl" xml:lang="en-US" id="id_1835722_533986_2_1">Backlog</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_BacklogMember" xlink:to="mrcy_BacklogMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:label="us-gaap_BasisOfAccountingPolicyPolicyTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BasisOfAccountingPolicyPolicyTextBlock_lbl" xml:lang="en-US" id="id_1835722_498043_1_1">Basis Of Accounting Policy Policy [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BasisOfAccountingPolicyPolicyTextBlock_lbl" xml:lang="en-US" id="id_1835722_498043_2_1">Basis of Presentation</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:to="us-gaap_BasisOfAccountingPolicyPolicyTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_lbl" xml:lang="en-US" id="id_1835722_503813_1_1">Business Acquisition Acquiree [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_lbl" xml:lang="en-US" id="id_1835722_503813_2_1">Business Acquisition, Acquiree [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="us-gaap_BusinessAcquisitionAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionAxis_lbl" xml:lang="en-US" id="id_1835722_499577_1_1">Business Acquisition [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessAcquisitionAxis_lbl" xml:lang="en-US" id="id_1835722_499577_2_1">Business Acquisition</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_BusinessAcquisitionCostOfAcquiredEntityCashPaidForSettlementOfAcquireeStockOptions" xlink:label="mrcy_BusinessAcquisitionCostOfAcquiredEntityCashPaidForSettlementOfAcquireeStockOptions"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_BusinessAcquisitionCostOfAcquiredEntityCashPaidForSettlementOfAcquireeStockOptions_lbl" xml:lang="en-US" id="id_1835722_523213_3_1">Business Acquisition, Cost of Acquired Entity, Cash Paid for Settlement of Acquiree Stock Options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_BusinessAcquisitionCostOfAcquiredEntityCashPaidForSettlementOfAcquireeStockOptions_lbl" xml:lang="en-US" id="id_1835722_523213_1_1">Business Acquisition Cost Of Acquired Entity Cash Paid For Settlement Of Acquiree Stock Options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_BusinessAcquisitionCostOfAcquiredEntityCashPaidForSettlementOfAcquireeStockOptions_lbl" xml:lang="en-US" id="id_1835722_523213_2_1">Cash paid to shareholders and to settle vested options</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_BusinessAcquisitionCostOfAcquiredEntityCashPaidForSettlementOfAcquireeStockOptions" xlink:to="mrcy_BusinessAcquisitionCostOfAcquiredEntityCashPaidForSettlementOfAcquireeStockOptions_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice" xlink:label="us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_lbl" xml:lang="en-US" id="id_1835722_509028_1_1">Business Acquisition Cost Of Acquired Entity Purchase Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_lbl" xml:lang="en-US" id="id_1835722_509028_6_1">Net purchase price</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice" xlink:to="us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_BusinessAcquisitionFairValueOfUnvestedEmployeeShareBasedAwardsAssumed" xlink:label="mrcy_BusinessAcquisitionFairValueOfUnvestedEmployeeShareBasedAwardsAssumed"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_BusinessAcquisitionFairValueOfUnvestedEmployeeShareBasedAwardsAssumed_lbl" xml:lang="en-US" id="id_1835722_556127_3_1">Business Acquisition Fair Value Of Unvested Employee Share Based Awards Assumed</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_BusinessAcquisitionFairValueOfUnvestedEmployeeShareBasedAwardsAssumed_lbl" xml:lang="en-US" id="id_1835722_556127_1_1">Business Acquisition Fair Value Of Unvested Employee Share Based Awards Assumed</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_BusinessAcquisitionFairValueOfUnvestedEmployeeShareBasedAwardsAssumed_lbl" xml:lang="en-US" id="id_1835722_556127_2_1">Value allocated to unvested options</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_BusinessAcquisitionFairValueOfUnvestedEmployeeShareBasedAwardsAssumed" xlink:to="mrcy_BusinessAcquisitionFairValueOfUnvestedEmployeeShareBasedAwardsAssumed_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="us-gaap_BusinessAcquisitionLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionLineItems_lbl" xml:lang="en-US" id="id_1835722_503555_1_1">Business Acquisition [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessAcquisitionLineItems_lbl" xml:lang="en-US" id="id_1835722_503555_2_1">Business Acquisition [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessAcquisitionLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_BusinessAcquisitionPurchasePriceAllocationAccountsPayableAndAccruedLiabilities" xlink:label="mrcy_BusinessAcquisitionPurchasePriceAllocationAccountsPayableAndAccruedLiabilities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_BusinessAcquisitionPurchasePriceAllocationAccountsPayableAndAccruedLiabilities_lbl" xml:lang="en-US" id="id_1835722_520333_3_1">Business Acquisition, Purchase Price Allocation, Accounts Payable and Accrued Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_BusinessAcquisitionPurchasePriceAllocationAccountsPayableAndAccruedLiabilities_lbl" xml:lang="en-US" id="id_1835722_520333_1_1">Business Acquisition Purchase Price Allocation Accounts Payable And Accrued Liabilities</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="mrcy_BusinessAcquisitionPurchasePriceAllocationAccountsPayableAndAccruedLiabilities_lbl" xml:lang="en-US" id="id_1835722_520333_8_1">Accounts payable and accrued expenses</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_BusinessAcquisitionPurchasePriceAllocationAccountsPayableAndAccruedLiabilities" xlink:to="mrcy_BusinessAcquisitionPurchasePriceAllocationAccountsPayableAndAccruedLiabilities_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquired" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquired"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquired_lbl" xml:lang="en-US" id="id_1835722_511023_1_1">Business Acquisition Purchase Price Allocation Assets Acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquired_lbl" xml:lang="en-US" id="id_1835722_511023_6_1">Estimated fair value of assets acquired</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquired" xlink:to="us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquired_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquiredLiabilitiesAssumedNetAbstract" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquiredLiabilitiesAssumedNetAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquiredLiabilitiesAssumedNetAbstract_lbl" xml:lang="en-US" id="id_1835722_504675_1_1">Business Acquisition Purchase Price Allocation Assets Acquired Liabilities Assumed Net [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquiredLiabilitiesAssumedNetAbstract_lbl" xml:lang="en-US" id="id_1835722_504675_2_1">Estimated fair value of tangible assets acquired and liabilities assumed</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquiredLiabilitiesAssumedNetAbstract" xlink:to="us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquiredLiabilitiesAssumedNetAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalents" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalents"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalents_lbl" xml:lang="en-US" id="id_1835722_498542_1_1">Business Acquisition Purchase Price Allocation Current Assets Cash And Cash Equivalents</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalents_lbl" xml:lang="en-US" id="id_1835722_498542_2_1">Cash</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalents" xlink:to="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalents_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalentsAcquired" xlink:label="mrcy_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalentsAcquired"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalentsAcquired_lbl" xml:lang="en-US" id="id_1835722_604854_3_1">Business Acquisition, Purchase Price Allocation, Current Assets, Cash and Cash Equivalents Acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalentsAcquired_lbl" xml:lang="en-US" id="id_1835722_604854_1_1">Business Acquisition Purchase Price Allocation Current Assets Cash And Cash Equivalents Acquired</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="mrcy_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalentsAcquired_lbl" xml:lang="en-US" id="id_1835722_604854_8_1">Less cash acquired</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalentsAcquired" xlink:to="mrcy_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalentsAcquired_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsInventory" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsInventory"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsInventory_lbl" xml:lang="en-US" id="id_1835722_514189_1_1">Business Acquisition Purchase Price Allocation Current Assets Inventory</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsInventory_lbl" xml:lang="en-US" id="id_1835722_514189_2_1">Inventory</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsInventory" xlink:to="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsInventory_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsReceivables" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsReceivables"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsReceivables_lbl" xml:lang="en-US" id="id_1835722_498303_1_1">Business Acquisition Purchase Price Allocation Current Assets Receivables</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsReceivables_lbl" xml:lang="en-US" id="id_1835722_498303_2_1">Accounts receivable</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xml:lang="en-US" id="id_1835722_510226_1_1">Common Stock Shares Issued</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="us-gaap_CommonStockSharesOutstanding"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xml:lang="en-US" id="id_1835722_504150_1_1">Common Stock Shares Outstanding</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockSharesOutstanding" xlink:to="us-gaap_CommonStockSharesOutstanding_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockValue_lbl" xml:lang="en-US" id="id_1835722_512456_1_1">Common Stock Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommonStockValue_lbl" xml:lang="en-US" id="id_1835722_512456_2_1">Common stock, $.01 par value; 85,000,000 shares authorized; 30,259,687 and 29,729,065 shares issued and outstanding at March 31, 2013 and June 30, 2012, respectively</label>
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    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_CompletedTechnologyMember" xlink:label="mrcy_CompletedTechnologyMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_CompletedTechnologyMember_lbl" xml:lang="en-US" id="id_1835722_535965_3_1">Completed Technology [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_CompletedTechnologyMember_lbl" xml:lang="en-US" id="id_1835722_535965_1_1">Completed Technology [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_CompletedTechnologyMember_lbl" xml:lang="en-US" id="id_1835722_535965_2_1">Completed Technologies</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ComponentOfOperatingOtherCostAndExpenseLineItems" xlink:label="us-gaap_ComponentOfOperatingOtherCostAndExpenseLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ComponentOfOperatingOtherCostAndExpenseLineItems_lbl" xml:lang="en-US" id="id_1835722_502602_1_1">Component Of Operating Other Cost And Expense [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ComponentOfOperatingOtherCostAndExpenseLineItems_lbl" xml:lang="en-US" id="id_1835722_502602_2_1">Component of Operating Other Cost and Expense [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ComponentOfOperatingOtherCostAndExpenseLineItems" xlink:to="us-gaap_ComponentOfOperatingOtherCostAndExpenseLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ComponentOfOtherOperatingCostAndExpenseTable" xlink:label="us-gaap_ComponentOfOtherOperatingCostAndExpenseTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ComponentOfOtherOperatingCostAndExpenseTable_lbl" xml:lang="en-US" id="id_1835722_504745_1_1">Component Of Other Operating Cost And Expense [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ComponentOfOtherOperatingCostAndExpenseTable_lbl" xml:lang="en-US" id="id_1835722_504745_2_1">Component of Other Operating Cost and Expense [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ComponentOfOtherOperatingCostAndExpenseTable" xlink:to="us-gaap_ComponentOfOtherOperatingCostAndExpenseTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax_lbl" xml:lang="en-US" id="id_1835722_500373_1_1">Comprehensive Income Net Of Tax</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax_lbl" xml:lang="en-US" id="id_1835722_500373_6_1">Total comprehensive income (loss)</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_ComprehensiveIncomeNetOfTax_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAbstract" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxAbstract_lbl" xml:lang="en-US" id="id_1835722_509678_1_1">Comprehensive Income Net Of Tax [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxAbstract_lbl" xml:lang="en-US" id="id_1835722_509678_2_1">Comprehensive income (loss):</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ComprehensiveIncomeNetOfTaxAbstract" xlink:to="us-gaap_ComprehensiveIncomeNetOfTaxAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="us-gaap_ConcentrationRiskByTypeAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConcentrationRiskByTypeAxis_lbl" xml:lang="en-US" id="id_1835722_502625_1_1">Concentration Risk By Type [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConcentrationRiskByTypeAxis_lbl" xml:lang="en-US" id="id_1835722_502625_2_1">Concentration Risk Type</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskByTypeAxis" xlink:to="us-gaap_ConcentrationRiskByTypeAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="us-gaap_ConcentrationRiskPercentage1"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConcentrationRiskPercentage1_lbl" xml:lang="en-US" id="id_1835722_500543_1_1">Concentration Risk Percentage 1</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConcentrationRiskPercentage1_lbl" xml:lang="en-US" id="id_1835722_500543_2_1">Percent of company revenue</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ConcentrationRiskPercentage1_lbl" xml:lang="en-US" id="id_1835722_500543_12_1">Percentage of revenue contributed from a single program</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskPercentage1" xlink:to="us-gaap_ConcentrationRiskPercentage1_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="us-gaap_ConcentrationRiskTypeDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConcentrationRiskTypeDomain_lbl" xml:lang="en-US" id="id_1835722_509340_1_1">Concentration Risk Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConcentrationRiskTypeDomain_lbl" xml:lang="en-US" id="id_1835722_509340_2_1">Concentration Risk Type [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskTypeDomain" xlink:to="us-gaap_ConcentrationRiskTypeDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CostOfRevenue" xlink:label="us-gaap_CostOfRevenue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CostOfRevenue_lbl" xml:lang="en-US" id="id_1835722_508522_1_1">Cost Of Revenue</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CostOfRevenue_lbl" xml:lang="en-US" id="id_1835722_508522_2_1">Cost of revenues</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CostOfRevenue" xlink:to="us-gaap_CostOfRevenue_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="us-gaap_CostOfSalesMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CostOfSalesMember_lbl" xml:lang="en-US" id="id_1835722_500840_1_1">Cost Of Sales [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CostOfSalesMember_lbl" xml:lang="en-US" id="id_1835722_500840_2_1">Cost of revenues</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CostOfSalesMember" xlink:to="us-gaap_CostOfSalesMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrProgramsExpectedToBeCollectedWithinOneYear" xlink:label="us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrProgramsExpectedToBeCollectedWithinOneYear"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrProgramsExpectedToBeCollectedWithinOneYear_lbl" xml:lang="en-US" id="id_1835722_512841_1_1">Costs In Excess Of Billings On Uncompleted Contracts Or Programs Expected To Be Collected Within One Year</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrProgramsExpectedToBeCollectedWithinOneYear_lbl" xml:lang="en-US" id="id_1835722_512841_2_1">Unbilled receivables and costs in excess of billings</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrProgramsExpectedToBeCollectedWithinOneYear" xlink:to="us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrProgramsExpectedToBeCollectedWithinOneYear_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="us-gaap_CreditFacilityAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CreditFacilityAxis_lbl" xml:lang="en-US" id="id_1835722_501572_1_1">Credit Facility [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CreditFacilityAxis_lbl" xml:lang="en-US" id="id_1835722_501572_2_1">Credit Facility</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="us-gaap_CreditFacilityDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CreditFacilityDomain_lbl" xml:lang="en-US" id="id_1835722_504885_1_1">Credit Facility [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CreditFacilityDomain_lbl" xml:lang="en-US" id="id_1835722_504885_2_1">Credit Facility [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="us-gaap_CreditFacilityDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="dei_CurrentFiscalYearEndDate"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xml:lang="en-US" id="id_1835722_497832_1_1">Current Fiscal Year End Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xml:lang="en-US" id="id_1835722_497832_2_1">Current Fiscal Year End Date</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_CurrentFiscalYearEndDate" xlink:to="dei_CurrentFiscalYearEndDate_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_CustomerOneMember" xlink:label="mrcy_CustomerOneMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_CustomerOneMember_lbl" xml:lang="en-US" id="id_1835722_518297_3_1">Customer 1 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_CustomerOneMember_lbl" xml:lang="en-US" id="id_1835722_518297_1_1">Customer One [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_CustomerOneMember_lbl" xml:lang="en-US" id="id_1835722_518297_2_1">Northrop Grumman Corporation</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_CustomerOneMember" xlink:to="mrcy_CustomerOneMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="us-gaap_CustomerRelationshipsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CustomerRelationshipsMember_lbl" xml:lang="en-US" id="id_1835722_513385_1_1">Customer Relationships [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CustomerRelationshipsMember_lbl" xml:lang="en-US" id="id_1835722_513385_2_1">Customer Relationships</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CustomerRelationshipsMember" xlink:to="us-gaap_CustomerRelationshipsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_CustomerThreeMember" xlink:label="mrcy_CustomerThreeMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_CustomerThreeMember_lbl" xml:lang="en-US" id="id_1835722_518299_3_1">Customer 3 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_CustomerThreeMember_lbl" xml:lang="en-US" id="id_1835722_518299_1_1">Customer Three [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_CustomerThreeMember_lbl" xml:lang="en-US" id="id_1835722_518299_2_1">Lockheed Martin Corporation</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_CustomerThreeMember" xlink:to="mrcy_CustomerThreeMember_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_Depreciation_lbl" xml:lang="en-US" id="id_1835722_511412_2_1">Depreciation</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EffectsOfChangesInPrepaymentEstimateAssumptionsForCMOsAndREMICsAffectedItemDomain_lbl" xml:lang="en-US" id="id_1835722_499853_2_1">Effects of Changes in Prepayment Estimate Assumptions for CMOs and REMICs, Affected Item [Domain]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl" xml:lang="en-US" id="id_1835722_503216_1_1">Employee Related Liabilities Current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl" xml:lang="en-US" id="id_1835722_503216_2_1">Accrued compensation</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:to="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_lbl" xml:lang="en-US" id="id_1835722_504933_1_1">Employee Service Share Based Compensation Allocation Of Recognized Period Costs Report Line [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_lbl" xml:lang="en-US" id="id_1835722_504933_2_1">Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Report Line [Domain]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_lbl" xml:lang="en-US" id="id_1835722_498974_1_1">Employee Service Share Based Compensation Tax Benefit From Compensation Expense</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_lbl" xml:lang="en-US" id="id_1835722_498974_8_1">Income taxes</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeStockMember" xlink:label="us-gaap_EmployeeStockMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EmployeeStockMember_lbl" xml:lang="en-US" id="id_1835722_509009_1_1">Employee Stock [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EmployeeStockMember_lbl" xml:lang="en-US" id="id_1835722_509009_2_1">1997 Employee Stock Purchase Plan</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeStockMember" xlink:to="us-gaap_EmployeeStockMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_EmployeeStockPurchasePlanMaximumPercentageOfCompensationToPurchaseSharesByEligibleParticipants" xlink:label="mrcy_EmployeeStockPurchasePlanMaximumPercentageOfCompensationToPurchaseSharesByEligibleParticipants"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_EmployeeStockPurchasePlanMaximumPercentageOfCompensationToPurchaseSharesByEligibleParticipants_lbl" xml:lang="en-US" id="id_1835722_540621_3_1">Employee Stock Purchase Plan, Maximum Percentage of Compensation to Purchase Shares By Eligible Participants</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_EmployeeStockPurchasePlanMaximumPercentageOfCompensationToPurchaseSharesByEligibleParticipants_lbl" xml:lang="en-US" id="id_1835722_540621_1_1">Employee Stock Purchase Plan Maximum Percentage Of Compensation To Purchase Shares By Eligible Participants</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_EmployeeStockPurchasePlanMaximumPercentageOfCompensationToPurchaseSharesByEligibleParticipants" xlink:to="mrcy_EmployeeStockPurchasePlanMaximumPercentageOfCompensationToPurchaseSharesByEligibleParticipants_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntitiesTable" xlink:label="dei_EntitiesTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="dei_EntitiesTable_lbl" xml:lang="en-US" id="id_1835722_497721_1_1">Entities [Table]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="dei_EntityCentralIndexKey"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="dei_EntityCentralIndexKey_lbl" xml:lang="en-US" id="id_1835722_497825_1_1">Entity Central Index Key</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="dei_EntityCentralIndexKey_lbl" xml:lang="en-US" id="id_1835722_497825_2_1">Entity Central Index Key</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="dei_EntityCommonStockSharesOutstanding"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xml:lang="en-US" id="id_1835722_497778_1_1">Entity Common Stock Shares Outstanding</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="dei_EntityDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="dei_EntityDomain_lbl" xml:lang="en-US" id="id_1835722_497798_1_1">Entity [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="dei_EntityDomain_lbl" xml:lang="en-US" id="id_1835722_497798_2_1">Entity [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityDomain" xlink:to="dei_EntityDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityFilerCategory" xlink:label="dei_EntityFilerCategory"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="dei_EntityFilerCategory_lbl" xml:lang="en-US" id="id_1835722_497731_1_1">Entity Filer Category</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="dei_EntityFilerCategory_lbl" xml:lang="en-US" id="id_1835722_497731_2_1">Entity Filer Category</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityFilerCategory" xlink:to="dei_EntityFilerCategory_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityRegistrantName" xlink:label="dei_EntityRegistrantName"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="dei_EntityRegistrantName_lbl" xml:lang="en-US" id="id_1835722_497713_1_1">Entity Registrant Name</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="dei_EntityRegistrantName_lbl" xml:lang="en-US" id="id_1835722_497713_2_1">Entity Registrant Name</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityRegistrantName" xlink:to="dei_EntityRegistrantName_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EntityWideDisclosureOnGeographicAreasLongLivedAssetsInEntitysCountryOfDomicile" xlink:label="us-gaap_EntityWideDisclosureOnGeographicAreasLongLivedAssetsInEntitysCountryOfDomicile"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EntityWideDisclosureOnGeographicAreasLongLivedAssetsInEntitysCountryOfDomicile_lbl" xml:lang="en-US" id="id_1835722_511276_1_1">Entity Wide Disclosure On Geographic Areas Long Lived Assets In Entitys Country Of Domicile</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EntityWideDisclosureOnGeographicAreasLongLivedAssetsInEntitysCountryOfDomicile_lbl" xml:lang="en-US" id="id_1835722_511276_2_1">Identifiable long-lived assets</label>
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    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToIndividualForeignCountries" xlink:label="mrcy_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToIndividualForeignCountries"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToIndividualForeignCountries_lbl" xml:lang="en-US" id="id_1835722_604858_3_1">Disclosure of material amounts of revenues from external customers by individual foreign country. In addition, an entity may provide subtotals of geographic information for specified groups of countries.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToIndividualForeignCountries_lbl" xml:lang="en-US" id="id_1835722_604858_1_1">Entity Wide Disclosure On Geographic Areas Revenue From External Customers Attributed To Individual Foreign Countries</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToIndividualForeignCountries_lbl" xml:lang="en-US" id="id_1835722_604858_2_1">Net revenues to unaffiliated customers</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:label="us-gaap_EntityWideRevenueMajorCustomerLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EntityWideRevenueMajorCustomerLineItems_lbl" xml:lang="en-US" id="id_1835722_499328_1_1">Entity Wide Revenue Major Customer [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EntityWideRevenueMajorCustomerLineItems_lbl" xml:lang="en-US" id="id_1835722_499328_2_1">Revenue, Major Customer [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:to="us-gaap_EntityWideRevenueMajorCustomerLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EntityWideRevenueMajorCustomerPercentage" xlink:label="us-gaap_EntityWideRevenueMajorCustomerPercentage"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EntityWideRevenueMajorCustomerPercentage_lbl" xml:lang="en-US" id="id_1835722_513522_1_1">Entity Wide Revenue Major Customer Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EntityWideRevenueMajorCustomerPercentage_lbl" xml:lang="en-US" id="id_1835722_513522_2_1">Revenue from Customers</label>
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    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_EuropeMember" xlink:label="mrcy_EuropeMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_EuropeMember_lbl" xml:lang="en-US" id="id_1835722_530825_3_1">Europe [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_EuropeMember_lbl" xml:lang="en-US" id="id_1835722_530825_1_1">Europe [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_EuropeMember_lbl" xml:lang="en-US" id="id_1835722_530825_2_1">Europe</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_EuropeMember" xlink:to="mrcy_EuropeMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:label="us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_lbl" xml:lang="en-US" id="id_1835722_513216_1_1">Excess Tax Benefit From Share Based Compensation Financing Activities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_lbl" xml:lang="en-US" id="id_1835722_513216_2_1">Excess tax benefits from stock-based compensation</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueDisclosureItemAmountsDomain_lbl" xml:lang="en-US" id="id_1835722_498288_1_1">Fair Value Disclosure Item Amounts [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueDisclosureItemAmountsDomain_lbl" xml:lang="en-US" id="id_1835722_498288_2_1">Fair Value, Disclosure Item Amounts [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueDisclosureItemAmountsDomain" xlink:to="us-gaap_FairValueDisclosureItemAmountsDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueDisclosuresAbstract" xlink:label="us-gaap_FairValueDisclosuresAbstract"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueDisclosuresAbstract_lbl" xml:lang="en-US" id="id_1835722_498434_2_1">Fair Value Disclosures [Abstract]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueDisclosuresTextBlock_lbl" xml:lang="en-US" id="id_1835722_502694_1_1">Fair Value Disclosures [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueDisclosuresTextBlock_lbl" xml:lang="en-US" id="id_1835722_502694_2_1">Fair Value of Financial Instruments</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xml:lang="en-US" id="id_1835722_508799_1_1">Fair Value Inputs Level 1 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xml:lang="en-US" id="id_1835722_508799_2_1">Fair Value, Inputs, Level 1</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xml:lang="en-US" id="id_1835722_501136_1_1">Fair Value Measurements Fair Value Hierarchy [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xml:lang="en-US" id="id_1835722_501136_2_1">Fair Value, Measurements, Fair Value Hierarchy [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_FairValueMeasurementsLineItems" xlink:label="mrcy_FairValueMeasurementsLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_FairValueMeasurementsLineItems_lbl" xml:lang="en-US" id="id_1835722_518941_3_1">Fair Value Measurements [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_FairValueMeasurementsLineItems_lbl" xml:lang="en-US" id="id_1835722_518941_1_1">Fair Value Measurements [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_FairValueMeasurementsLineItems_lbl" xml:lang="en-US" id="id_1835722_518941_2_1">Fair Value Measurements [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_FairValueMeasurementsLineItems" xlink:to="mrcy_FairValueMeasurementsLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_FairValueMeasurementsTable" xlink:label="mrcy_FairValueMeasurementsTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_FairValueMeasurementsTable_lbl" xml:lang="en-US" id="id_1835722_541950_3_1">Fair Value Measurements [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_FairValueMeasurementsTable_lbl" xml:lang="en-US" id="id_1835722_541950_1_1">Fair Value Measurements [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_FairValueMeasurementsTable_lbl" xml:lang="en-US" id="id_1835722_541950_2_1">Fair Value Measurements [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_FairValueMeasurementsTable" xlink:to="mrcy_FairValueMeasurementsTable_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_FairValueOfUnvestedStockOptionsAssumed" xlink:label="mrcy_FairValueOfUnvestedStockOptionsAssumed"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_FairValueOfUnvestedStockOptionsAssumed_lbl" xml:lang="en-US" id="id_1835722_580046_3_1">Fair Value Of Unvested Stock Options Assumed</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_FairValueOfUnvestedStockOptionsAssumed_lbl" xml:lang="en-US" id="id_1835722_580046_1_1">Fair Value Of Unvested Stock Options Assumed</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_FairValueOfUnvestedStockOptionsAssumed_lbl" xml:lang="en-US" id="id_1835722_580046_2_1">Unvested stock options assumed from Micronetics</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_FairValueOfUnvestedStockOptionsAssumed" xlink:to="mrcy_FairValueOfUnvestedStockOptionsAssumed_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_lbl" xml:lang="en-US" id="id_1835722_513029_1_1">Finite Lived Intangible Assets Accumulated Amortization</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_lbl" xml:lang="en-US" id="id_1835722_513029_8_1">Accumulated Amortization</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_lbl" xml:lang="en-US" id="id_1835722_505822_1_1">Finite Lived Intangible Assets Amortization Expense After Year Five</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_lbl" xml:lang="en-US" id="id_1835722_505822_2_1">Thereafter</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_lbl" xml:lang="en-US" id="id_1835722_506324_1_1">Finite Lived Intangible Assets Amortization Expense Next Twelve Months</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_lbl" xml:lang="en-US" id="id_1835722_506324_2_1">2013</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_lbl" xml:lang="en-US" id="id_1835722_502723_1_1">Finite Lived Intangible Assets Amortization Expense Year Five</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_lbl" xml:lang="en-US" id="id_1835722_502723_2_1">2017</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_lbl" xml:lang="en-US" id="id_1835722_511582_1_1">Finite Lived Intangible Assets Amortization Expense Year Four</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_lbl" xml:lang="en-US" id="id_1835722_511582_2_1">2016</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_lbl" xml:lang="en-US" id="id_1835722_500492_1_1">Finite Lived Intangible Assets Amortization Expense Year Three</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_lbl" xml:lang="en-US" id="id_1835722_500492_2_1">2015</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_lbl" xml:lang="en-US" id="id_1835722_511648_1_1">Finite Lived Intangible Assets Amortization Expense Year Two</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_lbl" xml:lang="en-US" id="id_1835722_511648_2_1">2014</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_lbl" xml:lang="en-US" id="id_1835722_513944_1_1">Finite Lived Intangible Assets By Major Class [Axis]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross_lbl" xml:lang="en-US" id="id_1835722_510135_2_1">Gross Carrying Amount</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_lbl" xml:lang="en-US" id="id_1835722_506045_1_1">Finite Lived Intangible Assets Major Class Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_lbl" xml:lang="en-US" id="id_1835722_506045_2_1">Finite-Lived Intangible Assets, Major Class Name [Domain]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xml:lang="en-US" id="id_1835722_500938_1_1">Finite Lived Intangible Assets Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xml:lang="en-US" id="id_1835722_500938_2_1">Net Carrying Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xml:lang="en-US" id="id_1835722_500938_6_1">Net Carrying Amount</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="us-gaap_FiniteLivedIntangibleAssetsNet_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_FuturePeriodMember" xlink:label="mrcy_FuturePeriodMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_FuturePeriodMember_lbl" xml:lang="en-US" id="id_1835722_533573_3_1">Future Period [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_FuturePeriodMember_lbl" xml:lang="en-US" id="id_1835722_533573_1_1">Future Period [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_FuturePeriodMember_lbl" xml:lang="en-US" id="id_1835722_533573_2_1">Fiscal Year 2013</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GeographicalIntersegmentEliminationsMember" xlink:label="us-gaap_GeographicalIntersegmentEliminationsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GeographicalIntersegmentEliminationsMember_lbl" xml:lang="en-US" id="id_1835722_505221_1_1">Geographical Intersegment Eliminations [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GeographicalIntersegmentEliminationsMember_lbl" xml:lang="en-US" id="id_1835722_505221_2_1">Geographical Intersegment, Eliminations</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Goodwill_lbl" xml:lang="en-US" id="id_1835722_498098_1_1">Goodwill</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_Goodwill_lbl" xml:lang="en-US" id="id_1835722_498098_4_1">Ending Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_Goodwill_lbl" xml:lang="en-US" id="id_1835722_498098_5_1">Beginning Balance</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Goodwill" xlink:to="us-gaap_Goodwill_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GoodwillAcquiredDuringPeriod" xlink:label="us-gaap_GoodwillAcquiredDuringPeriod"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GoodwillAcquiredDuringPeriod_lbl" xml:lang="en-US" id="id_1835722_513585_1_1">Goodwill Acquired During Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GoodwillAcquiredDuringPeriod_lbl" xml:lang="en-US" id="id_1835722_513585_2_1">Goodwill</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_lbl" xml:lang="en-US" id="id_1835722_512356_1_1">Goodwill And Intangible Assets Disclosure [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_lbl" xml:lang="en-US" id="id_1835722_512356_2_1">Goodwill and Intangible Assets Disclosure [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:to="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GoodwillDisclosureTextBlock" xlink:label="us-gaap_GoodwillDisclosureTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GoodwillDisclosureTextBlock_lbl" xml:lang="en-US" id="id_1835722_513619_1_1">Goodwill Disclosure [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GoodwillDisclosureTextBlock_lbl" xml:lang="en-US" id="id_1835722_513619_2_1">Goodwill</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillDisclosureTextBlock" xlink:to="us-gaap_GoodwillDisclosureTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_GoodwillImpairmentTestFairValueAssumptionsIncreaseDecreaseInDiscountRate" xlink:label="mrcy_GoodwillImpairmentTestFairValueAssumptionsIncreaseDecreaseInDiscountRate"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_GoodwillImpairmentTestFairValueAssumptionsIncreaseDecreaseInDiscountRate_lbl" xml:lang="en-US" id="id_1835722_604905_3_1">Goodwill Impairment Test, Fair Value Assumptions, Increase (Decrease) In Discount Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_GoodwillImpairmentTestFairValueAssumptionsIncreaseDecreaseInDiscountRate_lbl" xml:lang="en-US" id="id_1835722_604905_1_1">Goodwill Impairment Test Fair Value Assumptions Increase Decrease In Discount Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_GoodwillImpairmentTestFairValueAssumptionsIncreaseDecreaseInDiscountRate_lbl" xml:lang="en-US" id="id_1835722_604905_2_1">Increase in discount rate cash flow analysis result in failure of interim goodwill impairment test</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GoodwillLineItems" xlink:label="us-gaap_GoodwillLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GoodwillLineItems_lbl" xml:lang="en-US" id="id_1835722_502143_1_1">Goodwill [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GoodwillLineItems_lbl" xml:lang="en-US" id="id_1835722_502143_2_1">Goodwill [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillLineItems" xlink:to="us-gaap_GoodwillLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GoodwillPeriodIncreaseDecrease" xlink:label="us-gaap_GoodwillPeriodIncreaseDecrease"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GoodwillPeriodIncreaseDecrease_lbl" xml:lang="en-US" id="id_1835722_514580_2_1">Goodwill Adjustment</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GrossProfit" xlink:label="us-gaap_GrossProfit"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GrossProfit_lbl" xml:lang="en-US" id="id_1835722_511603_1_1">Gross Profit</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_GrossProfit_lbl" xml:lang="en-US" id="id_1835722_511603_6_1">Gross margin</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GrossProfit" xlink:to="us-gaap_GrossProfit_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_lbl" xml:lang="en-US" id="id_1835722_507631_1_1">Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_lbl" xml:lang="en-US" id="id_1835722_507631_2_1">(Loss) income from operations before income taxes</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_lbl" xml:lang="en-US" id="id_1835722_507631_6_1">(Loss) income from operations before income taxes</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:label="us-gaap_IncomeLossFromContinuingOperationsPerBasicShare"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_lbl" xml:lang="en-US" id="id_1835722_508527_1_1">Income Loss From Continuing Operations Per Basic Share</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_lbl" xml:lang="en-US" id="id_1835722_508527_2_1">Basic net earnings (loss) per share:</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_lbl" xml:lang="en-US" id="id_1835722_513873_1_1">Income Loss From Continuing Operations Per Diluted Share</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeStatementAbstract_lbl" xml:lang="en-US" id="id_1835722_509240_2_1">Income Statement [Abstract]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" xlink:label="us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable"/>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenueAndCustomerAdvancesAndDeposits" xlink:label="us-gaap_IncreaseDecreaseInDeferredRevenueAndCustomerAdvancesAndDeposits"/>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="us-gaap_IncreaseDecreaseInInventories"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInInventories_lbl" xml:lang="en-US" id="id_1835722_510295_1_1">Increase Decrease In Inventories</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncreaseDecreaseInInventories_lbl" xml:lang="en-US" id="id_1835722_510295_2_1">Increase in Inventory</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInInventories" xlink:to="us-gaap_IncreaseDecreaseInInventories_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xml:lang="en-US" id="id_1835722_503089_1_1">Increase Decrease In Operating Capital [Abstract]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestExpense_lbl" xml:lang="en-US" id="id_1835722_514855_1_1">Interest Expense</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_InterestExpense_lbl" xml:lang="en-US" id="id_1835722_514855_8_1">Interest expense</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestExpense" xlink:to="us-gaap_InterestExpense_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xml:lang="en-US" id="id_1835722_508651_1_1">Interest Income Expense Net</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xml:lang="en-US" id="id_1835722_508651_8_1">Interest expense, net</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryDisclosureAbstract" xlink:to="us-gaap_InventoryDisclosureAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InventoryDisclosureTextBlock" xlink:label="us-gaap_InventoryDisclosureTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InventoryDisclosureTextBlock_lbl" xml:lang="en-US" id="id_1835722_511327_1_1">Inventory Disclosure [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InventoryDisclosureTextBlock_lbl" xml:lang="en-US" id="id_1835722_511327_2_1">Inventory</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryDisclosureTextBlock" xlink:to="us-gaap_InventoryDisclosureTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:label="us-gaap_InventoryFinishedGoodsNetOfReserves"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InventoryFinishedGoodsNetOfReserves_lbl" xml:lang="en-US" id="id_1835722_512309_1_1">Inventory Finished Goods Net Of Reserves</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InventoryFinishedGoodsNetOfReserves_lbl" xml:lang="en-US" id="id_1835722_512309_2_1">Finished goods</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:to="us-gaap_InventoryFinishedGoodsNetOfReserves_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InventoryForLongTermContractsOrPrograms" xlink:label="us-gaap_InventoryForLongTermContractsOrPrograms"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InventoryForLongTermContractsOrPrograms_lbl" xml:lang="en-US" id="id_1835722_514592_1_1">Inventory For Long Term Contracts Or Programs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InventoryForLongTermContractsOrPrograms_lbl" xml:lang="en-US" id="id_1835722_514592_2_1">Inventory relating to contracts having production cycles longer than one year</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryForLongTermContractsOrPrograms" xlink:to="us-gaap_InventoryForLongTermContractsOrPrograms_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InventoryNet" xlink:label="us-gaap_InventoryNet"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InventoryNet_lbl" xml:lang="en-US" id="id_1835722_508278_1_1">Inventory Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InventoryNet_lbl" xml:lang="en-US" id="id_1835722_508278_2_1">Inventory</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_InventoryNet_lbl" xml:lang="en-US" id="id_1835722_508278_6_1">Total</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryNet" xlink:to="us-gaap_InventoryNet_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InventoryRawMaterialsNetOfReserves" xlink:label="us-gaap_InventoryRawMaterialsNetOfReserves"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InventoryRawMaterialsNetOfReserves_lbl" xml:lang="en-US" id="id_1835722_501846_1_1">Inventory Raw Materials Net Of Reserves</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InventoryRawMaterialsNetOfReserves_lbl" xml:lang="en-US" id="id_1835722_501846_2_1">Raw materials</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryRawMaterialsNetOfReserves" xlink:to="us-gaap_InventoryRawMaterialsNetOfReserves_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InventoryWorkInProcessNetOfReserves" xlink:label="us-gaap_InventoryWorkInProcessNetOfReserves"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InventoryWorkInProcessNetOfReserves_lbl" xml:lang="en-US" id="id_1835722_499915_1_1">Inventory Work In Process Net Of Reserves</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InventoryWorkInProcessNetOfReserves_lbl" xml:lang="en-US" id="id_1835722_499915_2_1">Work in process</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryWorkInProcessNetOfReserves" xlink:to="us-gaap_InventoryWorkInProcessNetOfReserves_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="us-gaap_InvestmentIncomeInterest"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InvestmentIncomeInterest_lbl" xml:lang="en-US" id="id_1835722_504284_1_1">Investment Income Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InvestmentIncomeInterest_lbl" xml:lang="en-US" id="id_1835722_504284_2_1">Interest income</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentIncomeInterest" xlink:to="us-gaap_InvestmentIncomeInterest_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_KeyBankCreditFacilityMember" xlink:label="mrcy_KeyBankCreditFacilityMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_KeyBankCreditFacilityMember_lbl" xml:lang="en-US" id="id_1835722_636138_3_1">Key Bank Credit Facility [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_KeyBankCreditFacilityMember_lbl" xml:lang="en-US" id="id_1835722_636138_1_1">Key Bank Credit Facility [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_KeyBankCreditFacilityMember_lbl" xml:lang="en-US" id="id_1835722_636138_2_1">KeyBank National Association</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_KeyBankCreditFacilityMember" xlink:to="mrcy_KeyBankCreditFacilityMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_KORElectronicsMember" xlink:label="mrcy_KORElectronicsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_KORElectronicsMember_lbl" xml:lang="en-US" id="id_1835722_601389_3_1">KOR Electronics [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_KORElectronicsMember_lbl" xml:lang="en-US" id="id_1835722_601389_1_1">K O R Electronics [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_KORElectronicsMember_lbl" xml:lang="en-US" id="id_1835722_601389_2_1">KOR Electronics</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_KORElectronicsMember" xlink:to="mrcy_KORElectronicsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="dei_LegalEntityAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="dei_LegalEntityAxis_lbl" xml:lang="en-US" id="id_1835722_497730_1_1">Legal Entity [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="dei_LegalEntityAxis_lbl" xml:lang="en-US" id="id_1835722_497730_2_1">Legal Entity [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_LegalEntityAxis" xlink:to="dei_LegalEntityAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="us-gaap_LettersOfCreditOutstandingAmount"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LettersOfCreditOutstandingAmount_lbl" xml:lang="en-US" id="id_1835722_510967_1_1">Letters Of Credit Outstanding Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LettersOfCreditOutstandingAmount_lbl" xml:lang="en-US" id="id_1835722_510967_2_1">Amount of outstanding letter of credit</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LettersOfCreditOutstandingAmount" xlink:to="us-gaap_LettersOfCreditOutstandingAmount_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_LeverageRatio" xlink:label="mrcy_LeverageRatio"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_LeverageRatio_lbl" xml:lang="en-US" id="id_1835722_519232_3_1">Leverage Ratio</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_LeverageRatio_lbl" xml:lang="en-US" id="id_1835722_519232_1_1">Leverage Ratio</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_LeverageRatio_lbl" xml:lang="en-US" id="id_1835722_519232_2_1">Leverage Ratio</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_LeverageRatio" xlink:to="mrcy_LeverageRatio_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Liabilities_lbl" xml:lang="en-US" id="id_1835722_506022_1_1">Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_Liabilities_lbl" xml:lang="en-US" id="id_1835722_506022_6_1">Total liabilities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_Liabilities_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xml:lang="en-US" id="id_1835722_508780_1_1">Liabilities And Stockholders Equity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xml:lang="en-US" id="id_1835722_508780_6_1">Total liabilities and shareholders' equity</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_LiabilitiesAndStockholdersEquity_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xml:lang="en-US" id="id_1835722_501524_1_1">Liabilities And Stockholders Equity [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xml:lang="en-US" id="id_1835722_501524_2_1">Liabilities and Shareholders' Equity</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="us-gaap_LiabilitiesCurrent"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xml:lang="en-US" id="id_1835722_511950_1_1">Liabilities Current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xml:lang="en-US" id="id_1835722_511950_6_1">Total current liabilities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_LiabilitiesCurrent_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="us-gaap_LiabilitiesCurrentAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xml:lang="en-US" id="id_1835722_510138_1_1">Liabilities Current [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xml:lang="en-US" id="id_1835722_510138_2_1">Current liabilities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_LiabilitiesCurrentAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityAmountOutstanding" xlink:label="us-gaap_LineOfCreditFacilityAmountOutstanding"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityAmountOutstanding_lbl" xml:lang="en-US" id="id_1835722_504418_1_1">Line Of Credit Facility Amount Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityAmountOutstanding_lbl" xml:lang="en-US" id="id_1835722_504418_2_1">Borrowings outstanding</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityAmountOutstanding" xlink:to="us-gaap_LineOfCreditFacilityAmountOutstanding_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:label="us-gaap_LineOfCreditFacilityAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityAxis_lbl" xml:lang="en-US" id="id_1835722_507199_1_1">Line Of Credit Facility [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityAxis_lbl" xml:lang="en-US" id="id_1835722_507199_2_1">Lender Name [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityAxis" xlink:to="us-gaap_LineOfCreditFacilityAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="us-gaap_LineOfCreditFacilityLenderDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityLenderDomain_lbl" xml:lang="en-US" id="id_1835722_504794_1_1">Line Of Credit Facility Lender [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityLenderDomain_lbl" xml:lang="en-US" id="id_1835722_504794_2_1">Line of Credit Facility, Lender [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityLenderDomain" xlink:to="us-gaap_LineOfCreditFacilityLenderDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xml:lang="en-US" id="id_1835722_507704_1_1">Line Of Credit Facility Maximum Borrowing Capacity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xml:lang="en-US" id="id_1835722_507704_2_1">Maximum borrowing capacity</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_LineOfCreditFacilityPermitsAdditionalBorrowingsAccordionFeature" xlink:label="mrcy_LineOfCreditFacilityPermitsAdditionalBorrowingsAccordionFeature"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_LineOfCreditFacilityPermitsAdditionalBorrowingsAccordionFeature_lbl" xml:lang="en-US" id="id_1835722_589667_3_1">Line of Credit Facility Permits, Additional Borrowings, Accordion Feature</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_LineOfCreditFacilityPermitsAdditionalBorrowingsAccordionFeature_lbl" xml:lang="en-US" id="id_1835722_589667_1_1">Line Of Credit Facility Permits Additional Borrowings Accordion Feature</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_LineOfCreditFacilityPermitsAdditionalBorrowingsAccordionFeature_lbl" xml:lang="en-US" id="id_1835722_589667_2_1">Credit Agreement accordion feature, incremental revolver or term loan amount</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_LineOfCreditFacilityPermitsAdditionalBorrowingsAccordionFeature" xlink:to="mrcy_LineOfCreditFacilityPermitsAdditionalBorrowingsAccordionFeature_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:label="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_lbl" xml:lang="en-US" id="id_1835722_510040_1_1">Line Of Credit Facility Remaining Borrowing Capacity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_lbl" xml:lang="en-US" id="id_1835722_510040_2_1">Remaining borrowing capacity</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:to="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_lbl" xml:lang="en-US" id="id_1835722_501211_1_1">Long Term Purchase Commitment By Category Of Item Purchased [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_lbl" xml:lang="en-US" id="id_1835722_501211_2_1">Category of Item Purchased</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis" xlink:to="us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" xlink:label="us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_lbl" xml:lang="en-US" id="id_1835722_504622_1_1">Long Term Purchase Commitment Category Of Item Purchased [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_lbl" xml:lang="en-US" id="id_1835722_504622_2_1">Long-term Purchase Commitment, Category of Item Purchased [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" xlink:to="us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermPurchaseCommitmentLineItems" xlink:label="us-gaap_LongTermPurchaseCommitmentLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermPurchaseCommitmentLineItems_lbl" xml:lang="en-US" id="id_1835722_512561_1_1">Long Term Purchase Commitment [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermPurchaseCommitmentLineItems_lbl" xml:lang="en-US" id="id_1835722_512561_2_1">Long-term Purchase Commitment [Line Items]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermPurchaseCommitmentTable" xlink:label="us-gaap_LongTermPurchaseCommitmentTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermPurchaseCommitmentTable_lbl" xml:lang="en-US" id="id_1835722_505423_1_1">Long Term Purchase Commitment [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermPurchaseCommitmentTable_lbl" xml:lang="en-US" id="id_1835722_505423_2_1">Long-term Purchase Commitment [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermPurchaseCommitmentTable" xlink:to="us-gaap_LongTermPurchaseCommitmentTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl" xml:lang="en-US" id="id_1835722_512812_1_1">Loss Contingencies By Nature Of Contingency [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl" xml:lang="en-US" id="id_1835722_512812_2_1">Loss Contingency Nature [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:to="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="us-gaap_LossContingencyNatureDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LossContingencyNatureDomain_lbl" xml:lang="en-US" id="id_1835722_514089_1_1">Loss Contingency Nature [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LossContingencyNatureDomain_lbl" xml:lang="en-US" id="id_1835722_514089_2_1">Loss Contingency, Nature [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LossContingencyNatureDomain" xlink:to="us-gaap_LossContingencyNatureDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="us-gaap_MajorCustomersAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MajorCustomersAxis_lbl" xml:lang="en-US" id="id_1835722_500094_1_1">Major Customers [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MajorCustomersAxis_lbl" xml:lang="en-US" id="id_1835722_500094_2_1">Major Customers</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MajorCustomersAxis" xlink:to="us-gaap_MajorCustomersAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="us-gaap_MaximumMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MaximumMember_lbl" xml:lang="en-US" id="id_1835722_514053_1_1">Maximum [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MaximumMember_lbl" xml:lang="en-US" id="id_1835722_514053_2_1">Maximum</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MaximumMember" xlink:to="us-gaap_MaximumMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_MercuryCommercialElectronicsMember" xlink:label="mrcy_MercuryCommercialElectronicsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_MercuryCommercialElectronicsMember_lbl" xml:lang="en-US" id="id_1835722_696174_3_1">Mercury Commercial Electronics [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_MercuryCommercialElectronicsMember_lbl" xml:lang="en-US" id="id_1835722_696174_1_1">Mercury Commercial Electronics [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_MercuryCommercialElectronicsMember_lbl" xml:lang="en-US" id="id_1835722_696174_2_1">Mercury Commercial Electronics</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_MercuryCommercialElectronicsMember" xlink:to="mrcy_MercuryCommercialElectronicsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_MercuryDefenseAndIntelligenceSystemsMember" xlink:label="mrcy_MercuryDefenseAndIntelligenceSystemsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_MercuryDefenseAndIntelligenceSystemsMember_lbl" xml:lang="en-US" id="id_1835722_696177_3_1">Mercury Defense and Intelligence Systems [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_MercuryDefenseAndIntelligenceSystemsMember_lbl" xml:lang="en-US" id="id_1835722_696177_1_1">Mercury Defense And Intelligence Systems [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_MercuryDefenseAndIntelligenceSystemsMember_lbl" xml:lang="en-US" id="id_1835722_696177_2_1">Mercury Defense and Intelligence Systems</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_MercuryDefenseAndIntelligenceSystemsMember" xlink:to="mrcy_MercuryDefenseAndIntelligenceSystemsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_MercuryDefenseSystemsMember" xlink:label="mrcy_MercuryDefenseSystemsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_MercuryDefenseSystemsMember_lbl" xml:lang="en-US" id="id_1835722_696175_3_1">Mercury Defense Systems [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_MercuryDefenseSystemsMember_lbl" xml:lang="en-US" id="id_1835722_696175_1_1">Mercury Defense Systems [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_MercuryDefenseSystemsMember_lbl" xml:lang="en-US" id="id_1835722_696175_2_1">Mercury Defense Systems</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_MercuryDefenseSystemsMember" xlink:to="mrcy_MercuryDefenseSystemsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_MercuryFederalSystemsMember" xlink:label="mrcy_MercuryFederalSystemsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_MercuryFederalSystemsMember_lbl" xml:lang="en-US" id="id_1835722_601397_3_1">Mercury Federal Systems [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_MercuryFederalSystemsMember_lbl" xml:lang="en-US" id="id_1835722_601397_1_1">Mercury Federal Systems [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_MercuryFederalSystemsMember_lbl" xml:lang="en-US" id="id_1835722_601397_2_1">MFS</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_MercuryFederalSystemsMember" xlink:to="mrcy_MercuryFederalSystemsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_MercuryIntelligenceSystemsMember" xlink:label="mrcy_MercuryIntelligenceSystemsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_MercuryIntelligenceSystemsMember_lbl" xml:lang="en-US" id="id_1835722_696176_3_1">Mercury Intelligence Systems [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_MercuryIntelligenceSystemsMember_lbl" xml:lang="en-US" id="id_1835722_696176_1_1">Mercury Intelligence Systems [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_MercuryIntelligenceSystemsMember_lbl" xml:lang="en-US" id="id_1835722_696176_2_1">Mercury Intelligence Systems</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_MercuryIntelligenceSystemsMember" xlink:to="mrcy_MercuryIntelligenceSystemsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_MicroneticsMember" xlink:label="mrcy_MicroneticsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_MicroneticsMember_lbl" xml:lang="en-US" id="id_1835722_601410_3_1">Micronetics [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_MicroneticsMember_lbl" xml:lang="en-US" id="id_1835722_601410_1_1">Micronetics [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_MicroneticsMember_lbl" xml:lang="en-US" id="id_1835722_601410_2_1">Micronetics</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_MicroneticsMember" xlink:to="mrcy_MicroneticsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_MinimumGrantDateFairValueOfNonqualifiedStockOptionsAsPercentageOfFairValueOfCommonStock" xlink:label="mrcy_MinimumGrantDateFairValueOfNonqualifiedStockOptionsAsPercentageOfFairValueOfCommonStock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_MinimumGrantDateFairValueOfNonqualifiedStockOptionsAsPercentageOfFairValueOfCommonStock_lbl" xml:lang="en-US" id="id_1835722_540914_3_1">Minimum Grant Date Fair Value Of Nonqualified Stock Options As Percentage Of Fair Value Of Common Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_MinimumGrantDateFairValueOfNonqualifiedStockOptionsAsPercentageOfFairValueOfCommonStock_lbl" xml:lang="en-US" id="id_1835722_540914_1_1">Minimum Grant Date Fair Value Of Nonqualified Stock Options As Percentage Of Fair Value Of Common Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_MinimumGrantDateFairValueOfNonqualifiedStockOptionsAsPercentageOfFairValueOfCommonStock_lbl" xml:lang="en-US" id="id_1835722_540914_2_1">Exercise price of stock option, percentage</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_MinimumGrantDateFairValueOfNonqualifiedStockOptionsAsPercentageOfFairValueOfCommonStock" xlink:to="mrcy_MinimumGrantDateFairValueOfNonqualifiedStockOptionsAsPercentageOfFairValueOfCommonStock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="us-gaap_MinimumMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MinimumMember_lbl" xml:lang="en-US" id="id_1835722_513639_1_1">Minimum [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MinimumMember_lbl" xml:lang="en-US" id="id_1835722_513639_2_1">Minimum</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MinimumMember" xlink:to="us-gaap_MinimumMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="us-gaap_NameOfMajorCustomerDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NameOfMajorCustomerDomain_lbl" xml:lang="en-US" id="id_1835722_504430_1_1">Name Of Major Customer [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NameOfMajorCustomerDomain_lbl" xml:lang="en-US" id="id_1835722_504430_2_1">Name of Major Customer [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="us-gaap_NameOfMajorCustomerDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NatureOfOperations" xlink:label="us-gaap_NatureOfOperations"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NatureOfOperations_lbl" xml:lang="en-US" id="id_1835722_507836_1_1">Nature Of Operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NatureOfOperations_lbl" xml:lang="en-US" id="id_1835722_507836_2_1">Description of Business</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NatureOfOperations" xlink:to="us-gaap_NatureOfOperations_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xml:lang="en-US" id="id_1835722_508099_1_1">Net Cash Provided By Used In Financing Activities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xml:lang="en-US" id="id_1835722_508099_6_1">Net cash (used in) provided by financing activities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xml:lang="en-US" id="id_1835722_503174_1_1">Net Cash Provided By Used In Financing Activities [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xml:lang="en-US" id="id_1835722_503174_2_1">Cash flows from financing activities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xml:lang="en-US" id="id_1835722_504277_1_1">Net Cash Provided By Used In Investing Activities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xml:lang="en-US" id="id_1835722_504277_6_1">Net cash used in investing activities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xml:lang="en-US" id="id_1835722_501589_1_1">Net Cash Provided By Used In Investing Activities [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xml:lang="en-US" id="id_1835722_501589_2_1">Cash flows from investing activities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xml:lang="en-US" id="id_1835722_504077_1_1">Net Cash Provided By Used In Operating Activities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xml:lang="en-US" id="id_1835722_504077_6_1">Net cash (used in) provided by operating activities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xml:lang="en-US" id="id_1835722_505595_1_1">Net Cash Provided By Used In Operating Activities [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xml:lang="en-US" id="id_1835722_505595_2_1">Cash flows from operating activities:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetIncomeLoss_lbl" xml:lang="en-US" id="id_1835722_513055_1_1">Net Income Loss</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetIncomeLoss_lbl" xml:lang="en-US" id="id_1835722_513055_2_1">Net (loss) income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetIncomeLoss_lbl" xml:lang="en-US" id="id_1835722_513055_6_1">Net income (loss)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_NetIncomeLoss_lbl" xml:lang="en-US" id="id_1835722_513055_12_1">Net income (loss)</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_NetIncomeLoss_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_NonCancelablePurchaseCommitmentsMember" xlink:label="mrcy_NonCancelablePurchaseCommitmentsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_NonCancelablePurchaseCommitmentsMember_lbl" xml:lang="en-US" id="id_1835722_601388_3_1">Non Cancelable Purchase Commitments [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_NonCancelablePurchaseCommitmentsMember_lbl" xml:lang="en-US" id="id_1835722_601388_1_1">Non Cancelable Purchase Commitments [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_NonCancelablePurchaseCommitmentsMember_lbl" xml:lang="en-US" id="id_1835722_601388_2_1">Non-cancelable purchase commitments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_NonCancelablePurchaseCommitmentsMember" xlink:to="mrcy_NonCancelablePurchaseCommitmentsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NoncompeteAgreementsMember" xlink:label="us-gaap_NoncompeteAgreementsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NoncompeteAgreementsMember_lbl" xml:lang="en-US" id="id_1835722_498774_1_1">Noncompete Agreements [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NoncompeteAgreementsMember_lbl" xml:lang="en-US" id="id_1835722_498774_2_1">Non-compete agreements</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoncompeteAgreementsMember" xlink:to="us-gaap_NoncompeteAgreementsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NumberOfOperatingSegments" xlink:label="us-gaap_NumberOfOperatingSegments"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NumberOfOperatingSegments_lbl" xml:lang="en-US" id="id_1835722_505781_1_1">Number Of Operating Segments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NumberOfOperatingSegments_lbl" xml:lang="en-US" id="id_1835722_505781_2_1">Number of Operating Segments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NumberOfOperatingSegments" xlink:to="us-gaap_NumberOfOperatingSegments_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_NumberOfReportableOperatingSegments" xlink:label="mrcy_NumberOfReportableOperatingSegments"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_NumberOfReportableOperatingSegments_lbl" xml:lang="en-US" id="id_1835722_558225_3_1">Number Of Reportable Operating Segments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_NumberOfReportableOperatingSegments_lbl" xml:lang="en-US" id="id_1835722_558225_1_1">Number Of Reportable Operating Segments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_NumberOfReportableOperatingSegments_lbl" xml:lang="en-US" id="id_1835722_558225_2_1">Number of Reportable Operating Segments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_NumberOfReportableOperatingSegments" xlink:to="mrcy_NumberOfReportableOperatingSegments_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingCycle" xlink:label="us-gaap_OperatingCycle"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingCycle_lbl" xml:lang="en-US" id="id_1835722_506929_1_1">Operating Cycle</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingCycle_lbl" xml:lang="en-US" id="id_1835722_506929_2_1">Production Cycle Term</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingCycle" xlink:to="us-gaap_OperatingCycle_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="us-gaap_OperatingExpenses"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingExpenses_lbl" xml:lang="en-US" id="id_1835722_509627_1_1">Operating Expenses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_OperatingExpenses_lbl" xml:lang="en-US" id="id_1835722_509627_6_1">Total operating expenses</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_OperatingExpenses_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="us-gaap_OperatingExpensesAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingExpensesAbstract_lbl" xml:lang="en-US" id="id_1835722_509338_1_1">Operating Expenses [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingExpensesAbstract_lbl" xml:lang="en-US" id="id_1835722_509338_2_1">Operating expenses:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_OperatingExpensesAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingIncomeLoss_lbl" xml:lang="en-US" id="id_1835722_498863_1_1">Operating Income Loss</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_OperatingIncomeLoss_lbl" xml:lang="en-US" id="id_1835722_498863_6_1">(Loss) income from operations</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingIncomeLoss" xlink:to="us-gaap_OperatingIncomeLoss_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="us-gaap_OtherAssetsNoncurrent"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xml:lang="en-US" id="id_1835722_500225_1_1">Other Assets Noncurrent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xml:lang="en-US" id="id_1835722_500225_2_1">Other non-current assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherAssetsNoncurrent" xlink:to="us-gaap_OtherAssetsNoncurrent_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_lbl" xml:lang="en-US" id="id_1835722_507555_1_1">Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_lbl" xml:lang="en-US" id="id_1835722_507555_2_1">Foreign currency translation adjustments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherIncomeAndExpensesAbstract" xlink:label="us-gaap_OtherIncomeAndExpensesAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherIncomeAndExpensesAbstract_lbl" xml:lang="en-US" id="id_1835722_511725_1_1">Other Income And Expenses [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherIncomeAndExpensesAbstract_lbl" xml:lang="en-US" id="id_1835722_511725_2_1">Other Income and Expenses [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_OtherIncomeAndExpensesAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="us-gaap_OtherLiabilitiesNoncurrent"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xml:lang="en-US" id="id_1835722_506871_1_1">Other Liabilities Noncurrent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xml:lang="en-US" id="id_1835722_506871_2_1">Other non-current liabilities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherLiabilitiesNoncurrent" xlink:to="us-gaap_OtherLiabilitiesNoncurrent_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:label="us-gaap_OtherNoncashIncomeExpense"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherNoncashIncomeExpense_lbl" xml:lang="en-US" id="id_1835722_498876_1_1">Other Noncash Income Expense</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_OtherNoncashIncomeExpense_lbl" xml:lang="en-US" id="id_1835722_498876_8_1">Other non-cash items</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherNoncashIncomeExpense" xlink:to="us-gaap_OtherNoncashIncomeExpense_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="us-gaap_OtherNonoperatingIncomeExpense"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherNonoperatingIncomeExpense_lbl" xml:lang="en-US" id="id_1835722_500036_1_1">Other Nonoperating Income Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherNonoperatingIncomeExpense_lbl" xml:lang="en-US" id="id_1835722_500036_2_1">Other income, net</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherNonoperatingIncomeExpense" xlink:to="us-gaap_OtherNonoperatingIncomeExpense_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_PatentsAndLicensingRightsMember" xlink:label="mrcy_PatentsAndLicensingRightsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_PatentsAndLicensingRightsMember_lbl" xml:lang="en-US" id="id_1835722_536923_3_1">Patents and Licensing Rights [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_PatentsAndLicensingRightsMember_lbl" xml:lang="en-US" id="id_1835722_536923_1_1">Patents And Licensing Rights [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_PatentsAndLicensingRightsMember_lbl" xml:lang="en-US" id="id_1835722_536923_2_1">Licensing agreements and patents</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_PatentsAndLicensingRightsMember" xlink:to="mrcy_PatentsAndLicensingRightsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities" xlink:label="us-gaap_PaymentsForProceedsFromOtherInvestingActivities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsForProceedsFromOtherInvestingActivities_lbl" xml:lang="en-US" id="id_1835722_511475_1_1">Payments For Proceeds From Other Investing Activities</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_PaymentsForProceedsFromOtherInvestingActivities_lbl" xml:lang="en-US" id="id_1835722_511475_8_1">Increase in other investing activities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsForProceedsFromOtherInvestingActivities" xlink:to="us-gaap_PaymentsForProceedsFromOtherInvestingActivities_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsForRestructuring" xlink:label="us-gaap_PaymentsForRestructuring"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsForRestructuring_lbl" xml:lang="en-US" id="id_1835722_510813_1_1">Payments For Restructuring</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_PaymentsForRestructuring_lbl" xml:lang="en-US" id="id_1835722_510813_8_1">Cash paid</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsForRestructuring" xlink:to="us-gaap_PaymentsForRestructuring_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts_lbl" xml:lang="en-US" id="id_1835722_510719_1_1">Payments Of Stock Issuance Costs</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts_lbl" xml:lang="en-US" id="id_1835722_510719_8_1">Payments of deferred financing and offering costs</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsOfStockIssuanceCosts" xlink:to="us-gaap_PaymentsOfStockIssuanceCosts_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_lbl" xml:lang="en-US" id="id_1835722_503220_1_1">Payments To Acquire Available For Sale Securities Debt</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_lbl" xml:lang="en-US" id="id_1835722_503220_8_1">Payments of acquired debt</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt" xlink:to="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" xml:lang="en-US" id="id_1835722_499811_1_1">Payments To Acquire Businesses Net Of Cash Acquired</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" xml:lang="en-US" id="id_1835722_499811_8_1">Acquisition of businesses, net of cash acquired</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:to="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquireIntangibleAssets" xlink:label="us-gaap_PaymentsToAcquireIntangibleAssets"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquireIntangibleAssets_lbl" xml:lang="en-US" id="id_1835722_512384_1_1">Payments To Acquire Intangible Assets</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_PaymentsToAcquireIntangibleAssets_lbl" xml:lang="en-US" id="id_1835722_512384_8_1">Payments for acquired intangible assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireIntangibleAssets" xlink:to="us-gaap_PaymentsToAcquireIntangibleAssets_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xml:lang="en-US" id="id_1835722_505828_1_1">Payments To Acquire Property Plant And Equipment</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xml:lang="en-US" id="id_1835722_505828_8_1">Purchases of property and equipment</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_PercentageOfCompanyRevenue" xlink:label="mrcy_PercentageOfCompanyRevenue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_PercentageOfCompanyRevenue_lbl" xml:lang="en-US" id="id_1835722_540538_3_1">Percentage of Company Revenue</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_PercentageOfCompanyRevenue_lbl" xml:lang="en-US" id="id_1835722_540538_1_1">Percentage Of Company Revenue</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_PercentageOfCompanyRevenue_lbl" xml:lang="en-US" id="id_1835722_540538_2_1">Percent of company revenue</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_PercentageOfCompanyRevenue" xlink:to="mrcy_PercentageOfCompanyRevenue_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="us-gaap_PlanNameAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PlanNameAxis_lbl" xml:lang="en-US" id="id_1835722_498429_1_1">Plan Name [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PlanNameAxis_lbl" xml:lang="en-US" id="id_1835722_498429_2_1">Plan Name</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameAxis" xlink:to="us-gaap_PlanNameAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="us-gaap_PlanNameDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PlanNameDomain_lbl" xml:lang="en-US" id="id_1835722_502068_1_1">Plan Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PlanNameDomain_lbl" xml:lang="en-US" id="id_1835722_502068_2_1">Plan Name [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameDomain" xlink:to="us-gaap_PlanNameDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" xml:lang="en-US" id="id_1835722_508638_1_1">Preferred Stock Par Or Stated Value Per Share</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" xml:lang="en-US" id="id_1835722_508638_2_1">Preferred stock, par value</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockParOrStatedValuePerShare" xlink:to="us-gaap_PreferredStockParOrStatedValuePerShare_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="us-gaap_PreferredStockSharesAuthorized"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xml:lang="en-US" id="id_1835722_507083_1_1">Preferred Stock Shares Authorized</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xml:lang="en-US" id="id_1835722_507083_2_1">Preferred stock, shares authorized</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockSharesAuthorized" xlink:to="us-gaap_PreferredStockSharesAuthorized_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="us-gaap_PreferredStockSharesIssued"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredStockSharesIssued_lbl" xml:lang="en-US" id="id_1835722_513613_1_1">Preferred Stock Shares Issued</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredStockSharesIssued_lbl" xml:lang="en-US" id="id_1835722_513613_2_1">Preferred stock, shares issued</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockSharesIssued" xlink:to="us-gaap_PreferredStockSharesIssued_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="us-gaap_PreferredStockSharesOutstanding"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xml:lang="en-US" id="id_1835722_513494_1_1">Preferred Stock Shares Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xml:lang="en-US" id="id_1835722_513494_2_1">Preferred stock, shares outstanding</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockSharesOutstanding" xlink:to="us-gaap_PreferredStockSharesOutstanding_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="us-gaap_PreferredStockValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredStockValue_lbl" xml:lang="en-US" id="id_1835722_513620_1_1">Preferred Stock Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredStockValue_lbl" xml:lang="en-US" id="id_1835722_513620_2_1">Preferred stock, $.01 par value; 1,000,000 shares authorized; no shares issued or outstanding</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredStockValue" xlink:to="us-gaap_PreferredStockValue_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xml:lang="en-US" id="id_1835722_497998_1_1">Prepaid Expense And Other Assets Current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xml:lang="en-US" id="id_1835722_497998_2_1">Prepaid expenses and other current assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PrepaidTaxes" xlink:label="us-gaap_PrepaidTaxes"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PrepaidTaxes_lbl" xml:lang="en-US" id="id_1835722_503633_1_1">Prepaid Taxes</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PrepaidTaxes_lbl" xml:lang="en-US" id="id_1835722_503633_2_1">Prepaid income taxes</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PrepaidTaxes" xlink:to="us-gaap_PrepaidTaxes_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromRepaymentsOfRestrictedCashFinancingActivities" xlink:label="us-gaap_ProceedsFromRepaymentsOfRestrictedCashFinancingActivities"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromRepaymentsOfRestrictedCashFinancingActivities_lbl" xml:lang="en-US" id="id_1835722_505099_1_1">Proceeds From Repayments Of Restricted Cash Financing Activities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromRepaymentsOfRestrictedCashFinancingActivities_lbl" xml:lang="en-US" id="id_1835722_505099_2_1">Decrease in restricted cash</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromRepaymentsOfRestrictedCashFinancingActivities" xlink:to="us-gaap_ProceedsFromRepaymentsOfRestrictedCashFinancingActivities_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="us-gaap_ProceedsFromStockOptionsExercised"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xml:lang="en-US" id="id_1835722_503911_1_1">Proceeds From Stock Options Exercised</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xml:lang="en-US" id="id_1835722_503911_2_1">Proceeds from employee stock plans</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromStockOptionsExercised" xlink:to="us-gaap_ProceedsFromStockOptionsExercised_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProductMember" xlink:label="us-gaap_ProductMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProductMember_lbl" xml:lang="en-US" id="id_1835722_512688_1_1">Product [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProductMember_lbl" xml:lang="en-US" id="id_1835722_512688_2_1">Product</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProductMember" xlink:to="us-gaap_ProductMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="us-gaap_ProductOrServiceAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProductOrServiceAxis_lbl" xml:lang="en-US" id="id_1835722_510496_1_1">Product Or Service [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProductOrServiceAxis_lbl" xml:lang="en-US" id="id_1835722_510496_2_1">Products and Services</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProductOrServiceAxis" xlink:to="us-gaap_ProductOrServiceAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="us-gaap_ProductsAndServicesDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProductsAndServicesDomain_lbl" xml:lang="en-US" id="id_1835722_509457_1_1">Products And Services [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProductsAndServicesDomain_lbl" xml:lang="en-US" id="id_1835722_509457_2_1">Products and Services [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProductsAndServicesDomain" xlink:to="us-gaap_ProductsAndServicesDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_ProgramFourMember" xlink:label="mrcy_ProgramFourMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_ProgramFourMember_lbl" xml:lang="en-US" id="id_1835722_696179_3_1">Program Four [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_ProgramFourMember_lbl" xml:lang="en-US" id="id_1835722_696179_1_1">Program Four [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_ProgramFourMember_lbl" xml:lang="en-US" id="id_1835722_696179_2_1">Patriot</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_ProgramFourMember" xlink:to="mrcy_ProgramFourMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_ProgramOneMember" xlink:label="mrcy_ProgramOneMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_ProgramOneMember_lbl" xml:lang="en-US" id="id_1835722_598844_3_1">Program One [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_ProgramOneMember_lbl" xml:lang="en-US" id="id_1835722_598844_1_1">Program One [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_ProgramOneMember_lbl" xml:lang="en-US" id="id_1835722_598844_2_1">Joint Strike Fighter</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_ProgramOneMember" xlink:to="mrcy_ProgramOneMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_ProgramThreeMember" xlink:label="mrcy_ProgramThreeMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_ProgramThreeMember_lbl" xml:lang="en-US" id="id_1835722_676260_3_1">Program Three [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_ProgramThreeMember_lbl" xml:lang="en-US" id="id_1835722_676260_1_1">Program Three [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_ProgramThreeMember_lbl" xml:lang="en-US" id="id_1835722_676260_2_1">Aegis</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_ProgramThreeMember" xlink:to="mrcy_ProgramThreeMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xml:lang="en-US" id="id_1835722_514011_1_1">Property Plant And Equipment Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xml:lang="en-US" id="id_1835722_514011_2_1">Property and equipment, net</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentNet" xlink:to="us-gaap_PropertyPlantAndEquipmentNet_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="us-gaap_RangeAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RangeAxis_lbl" xml:lang="en-US" id="id_1835722_504957_1_1">Range [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RangeAxis_lbl" xml:lang="en-US" id="id_1835722_504957_2_1">Range</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeAxis_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RangeMember_lbl" xml:lang="en-US" id="id_1835722_498452_1_1">Range [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_RevenuesFromTransactionsWithOtherGeographicLocationsOfSameEntity_lbl" xml:lang="en-US" id="id_1835722_604857_3_1">Amount of revenue from transactions with other geographic locations of the same entity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_RevenuesFromTransactionsWithOtherGeographicLocationsOfSameEntity_lbl" xml:lang="en-US" id="id_1835722_604857_1_1">Revenues From Transactions With Other Geographic Locations Of Same Entity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_RevenuesFromTransactionsWithOtherGeographicLocationsOfSameEntity_lbl" xml:lang="en-US" id="id_1835722_604857_2_1">Inter-geographic revenues</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RevenuesFromTransactionsWithOtherOperatingSegmentsOfSameEntity" xlink:label="us-gaap_RevenuesFromTransactionsWithOtherOperatingSegmentsOfSameEntity"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RevenuesFromTransactionsWithOtherOperatingSegmentsOfSameEntity_lbl" xml:lang="en-US" id="id_1835722_512191_1_1">Revenues From Transactions With Other Operating Segments Of Same Entity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RevenuesFromTransactionsWithOtherOperatingSegmentsOfSameEntity_lbl" xml:lang="en-US" id="id_1835722_512191_2_1">Intersegment revenues</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenuesFromTransactionsWithOtherOperatingSegmentsOfSameEntity" xlink:to="us-gaap_RevenuesFromTransactionsWithOtherOperatingSegmentsOfSameEntity_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SaleLeasebackTransactionDeferredGainNet" xlink:label="us-gaap_SaleLeasebackTransactionDeferredGainNet"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SaleLeasebackTransactionDeferredGainNet_lbl" xml:lang="en-US" id="id_1835722_508078_1_1">Sale Leaseback Transaction Deferred Gain Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SaleLeasebackTransactionDeferredGainNet_lbl" xml:lang="en-US" id="id_1835722_508078_2_1">Deferred gain on sale-leaseback</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SaleLeasebackTransactionDeferredGainNet" xlink:to="us-gaap_SaleLeasebackTransactionDeferredGainNet_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="us-gaap_ScenarioUnspecifiedDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScenarioUnspecifiedDomain_lbl" xml:lang="en-US" id="id_1835722_505562_1_1">Scenario Unspecified [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScenarioUnspecifiedDomain_lbl" xml:lang="en-US" id="id_1835722_505562_2_1">Scenario, Unspecified [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_ScenarioUnspecifiedDomain_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" xlink:label="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_lbl" xml:lang="en-US" id="id_1835722_507056_1_1">Schedule Of Acquired Finite Lived Intangible Asset By Major Class [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_lbl" xml:lang="en-US" id="id_1835722_507056_2_1">Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" xlink:to="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetsByMajorClassTextBlock" xlink:label="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetsByMajorClassTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetsByMajorClassTextBlock_lbl" xml:lang="en-US" id="id_1835722_511762_1_1">Schedule Of Acquired Finite Lived Intangible Assets By Major Class [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetsByMajorClassTextBlock_lbl" xml:lang="en-US" id="id_1835722_511762_2_1">Preliminary Estimated Fair Value of Acquired Intangible Assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetsByMajorClassTextBlock" xlink:to="us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetsByMajorClassTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_lbl" xml:lang="en-US" id="id_1835722_502564_1_1">Schedule Of Business Acquisitions By Acquisition [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_lbl" xml:lang="en-US" id="id_1835722_502564_2_1">Schedule of Business Acquisitions, by Acquisition [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis_lbl" xml:lang="en-US" id="id_1835722_498752_1_1">Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs By Report Line [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis_lbl" xml:lang="en-US" id="id_1835722_498752_2_1">Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs, by Report Line [Axis]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis" xlink:to="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_lbl" xml:lang="en-US" id="id_1835722_513471_1_1">Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_lbl" xml:lang="en-US" id="id_1835722_513471_2_1">Stock Based Compensation Expenses</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:to="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" xlink:label="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_lbl" xml:lang="en-US" id="id_1835722_501338_1_1">Schedule Of Entity Wide Revenue By Major Customers By Reporting Segments [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_lbl" xml:lang="en-US" id="id_1835722_501338_2_1">Schedule of Revenue by Major Customers, by Reporting Segments [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" xlink:to="us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:label="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_lbl" xml:lang="en-US" id="id_1835722_504401_1_1">Scheduleof Finite Lived Intangible Assets Future Amortization Expense Table [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_lbl" xml:lang="en-US" id="id_1835722_504401_2_1">Estimated Future Amortization Expense for Acquired Intangible Assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:to="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_lbl" xml:lang="en-US" id="id_1835722_505579_1_1">Schedule Of Finite Lived Intangible Assets Table [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_lbl" xml:lang="en-US" id="id_1835722_505579_2_1">Acquired Intangible Assets</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:to="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfGoodwillTable" xlink:label="us-gaap_ScheduleOfGoodwillTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfGoodwillTable_lbl" xml:lang="en-US" id="id_1835722_509460_1_1">Schedule Of Goodwill [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfGoodwillTable_lbl" xml:lang="en-US" id="id_1835722_509460_2_1">Schedule of Goodwill [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfGoodwillTable" xlink:to="us-gaap_ScheduleOfGoodwillTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfGoodwillTextBlock" xlink:label="us-gaap_ScheduleOfGoodwillTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfGoodwillTextBlock_lbl" xml:lang="en-US" id="id_1835722_504043_1_1">Schedule Of Goodwill [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfGoodwillTextBlock_lbl" xml:lang="en-US" id="id_1835722_504043_2_1">Changes in Carrying Amount of Goodwill</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfGoodwillTextBlock" xlink:to="us-gaap_ScheduleOfGoodwillTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfInventoryCurrentTableTextBlock" xlink:label="us-gaap_ScheduleOfInventoryCurrentTableTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfInventoryCurrentTableTextBlock_lbl" xml:lang="en-US" id="id_1835722_505840_1_1">Schedule Of Inventory Current Table [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfInventoryCurrentTableTextBlock_lbl" xml:lang="en-US" id="id_1835722_505840_2_1">Inventory</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfInventoryCurrentTableTextBlock" xlink:to="us-gaap_ScheduleOfInventoryCurrentTableTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_ScheduleOfInventoryLineItems" xlink:label="mrcy_ScheduleOfInventoryLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_ScheduleOfInventoryLineItems_lbl" xml:lang="en-US" id="id_1835722_518780_3_1">Schedule of Inventory [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_ScheduleOfInventoryLineItems_lbl" xml:lang="en-US" id="id_1835722_518780_1_1">Schedule Of Inventory [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_ScheduleOfInventoryLineItems_lbl" xml:lang="en-US" id="id_1835722_518780_2_1">Schedule of Inventory [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_ScheduleOfInventoryLineItems" xlink:to="mrcy_ScheduleOfInventoryLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_ScheduleOfInventoryTable" xlink:label="mrcy_ScheduleOfInventoryTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_ScheduleOfInventoryTable_lbl" xml:lang="en-US" id="id_1835722_541780_3_1">Schedule of Inventory [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_ScheduleOfInventoryTable_lbl" xml:lang="en-US" id="id_1835722_541780_1_1">Schedule Of Inventory [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_ScheduleOfInventoryTable_lbl" xml:lang="en-US" id="id_1835722_541780_2_1">Schedule of Inventory [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_ScheduleOfInventoryTable" xlink:to="mrcy_ScheduleOfInventoryTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:label="us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_lbl" xml:lang="en-US" id="id_1835722_504263_1_1">Schedule Of Nonvested Share Activity Table [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_lbl" xml:lang="en-US" id="id_1835722_504263_2_1">Summary of Nonvested Restricted Stock</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:to="us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_lbl"/>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:label="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock"/>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_lbl" xml:lang="en-US" id="id_1835722_513920_2_1">Schedule of Segment Reporting Information, by Segment [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" xml:lang="en-US" id="id_1835722_503859_1_1">Schedule Of Segment Reporting Information By Segment [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" xml:lang="en-US" id="id_1835722_503859_2_1">Summary of Performance of Operations by Reportable Segment</label>
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    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsLineItems" xlink:label="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsLineItems_lbl" xml:lang="en-US" id="id_1835722_518771_3_1">Schedule of Share based Compensation Arrangements by Share based Payment Award, Performance Options [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsLineItems_lbl" xml:lang="en-US" id="id_1835722_518771_1_1">Schedule Of Share Based Compensation Arrangements By Share Based Payment Award Performance Options [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsLineItems_lbl" xml:lang="en-US" id="id_1835722_518771_2_1">Schedule of Share based Compensation Arrangements by Share based Payment Award, Performance Options [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsLineItems" xlink:to="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsTable" xlink:label="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsTable_lbl" xml:lang="en-US" id="id_1835722_541702_3_1">Schedule of Share based Compensation Arrangements by Share based Payment Award, Performance Options [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsTable_lbl" xml:lang="en-US" id="id_1835722_541702_1_1">Schedule Of Share Based Compensation Arrangements By Share Based Payment Award Performance Options [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsTable_lbl" xml:lang="en-US" id="id_1835722_541702_2_1">Schedule of Share based Compensation Arrangements by Share based Payment Award, Performance Options [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsTable" xlink:to="mrcy_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceOptionsTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xml:lang="en-US" id="id_1835722_504588_1_1">Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xml:lang="en-US" id="id_1835722_504588_2_1">Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl"/>
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    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_ScheduleOfWeightedAverageNumberOfSharesOutstandingTable" xlink:label="mrcy_ScheduleOfWeightedAverageNumberOfSharesOutstandingTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_ScheduleOfWeightedAverageNumberOfSharesOutstandingTable_lbl" xml:lang="en-US" id="id_1835722_541732_3_1">Schedule of Weighted Average Number of Shares Outstanding [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_ScheduleOfWeightedAverageNumberOfSharesOutstandingTable_lbl" xml:lang="en-US" id="id_1835722_541732_1_1">Schedule Of Weighted Average Number Of Shares Outstanding [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_ScheduleOfWeightedAverageNumberOfSharesOutstandingTable_lbl" xml:lang="en-US" id="id_1835722_541732_2_1">Schedule of Weighted Average Number of Shares Outstanding [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_ScheduleOfWeightedAverageNumberOfSharesOutstandingTable" xlink:to="mrcy_ScheduleOfWeightedAverageNumberOfSharesOutstandingTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:label="us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock_lbl" xml:lang="en-US" id="id_1835722_509675_1_1">Schedule Of Weighted Average Number Of Shares Table [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock_lbl" xml:lang="en-US" id="id_1835722_509675_2_1">Basic and Diluted Weighted Average Shares Outstanding</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock" xlink:to="us-gaap_ScheduleOfWeightedAverageNumberOfSharesTableTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentDomain" xlink:label="us-gaap_SegmentDomain"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SegmentDomain_lbl" xml:lang="en-US" id="id_1835722_514551_1_1">Segment [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SegmentDomain_lbl" xml:lang="en-US" id="id_1835722_514551_2_1">Segment [Domain]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentDomain" xlink:to="us-gaap_SegmentDomain_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SegmentGeographicalDomain_lbl" xml:lang="en-US" id="id_1835722_503054_1_1">Segment Geographical [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SegmentGeographicalDomain_lbl" xml:lang="en-US" id="id_1835722_503054_2_1">Segment, Geographical [Domain]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SegmentReportingAbstract_lbl" xml:lang="en-US" id="id_1835722_513919_2_1">Segment Reporting [Abstract]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SegmentReportingInformationLineItems_lbl" xml:lang="en-US" id="id_1835722_508851_2_1">Segment Reporting Information [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_SegmentReportingInformationLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedLineItems" xlink:label="us-gaap_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedLineItems_lbl" xml:lang="en-US" id="id_1835722_505962_1_1">Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedLineItems_lbl" xml:lang="en-US" id="id_1835722_505962_2_1">Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedLineItems" xlink:to="us-gaap_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentReportingRevenueReconcilingItemLineItems" xlink:label="us-gaap_SegmentReportingRevenueReconcilingItemLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SegmentReportingRevenueReconcilingItemLineItems_lbl" xml:lang="en-US" id="id_1835722_511873_1_1">Segment Reporting Revenue Reconciling Item [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SegmentReportingRevenueReconcilingItemLineItems_lbl" xml:lang="en-US" id="id_1835722_511873_2_1">Segment Reporting, Revenue Reconciling Item [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingRevenueReconcilingItemLineItems" xlink:to="us-gaap_SegmentReportingRevenueReconcilingItemLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense_lbl" xml:lang="en-US" id="id_1835722_513334_1_1">Selling General And Administrative Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense_lbl" xml:lang="en-US" id="id_1835722_513334_2_1">Selling, general and administrative</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SellingGeneralAndAdministrativeExpense" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpense_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember_lbl" xml:lang="en-US" id="id_1835722_505060_1_1">Selling General And Administrative Expenses [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember_lbl" xml:lang="en-US" id="id_1835722_505060_2_1">Selling, general and administrative</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpensesMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_SeniorSecuredCreditFacilityMember" xlink:label="mrcy_SeniorSecuredCreditFacilityMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_SeniorSecuredCreditFacilityMember_lbl" xml:lang="en-US" id="id_1835722_533408_3_1">Senior Secured Credit Facility [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_SeniorSecuredCreditFacilityMember_lbl" xml:lang="en-US" id="id_1835722_533408_1_1">Senior Secured Credit Facility [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_SeniorSecuredCreditFacilityMember_lbl" xml:lang="en-US" id="id_1835722_533408_2_1">Senior Secured Credit Facility</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_SeniorSecuredCreditFacilityMember" xlink:to="mrcy_SeniorSecuredCreditFacilityMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_SeniorUnsecuredCreditFacilitiesMember" xlink:label="mrcy_SeniorUnsecuredCreditFacilitiesMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_SeniorUnsecuredCreditFacilitiesMember_lbl" xml:lang="en-US" id="id_1835722_564748_3_1">Senior Unsecured Credit Facilities [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_SeniorUnsecuredCreditFacilitiesMember_lbl" xml:lang="en-US" id="id_1835722_564748_1_1">Senior Unsecured Credit Facilities [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_SeniorUnsecuredCreditFacilitiesMember_lbl" xml:lang="en-US" id="id_1835722_564748_2_1">Senior Unsecured Credit Facilities</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_SeniorUnsecuredCreditFacilitiesMember" xlink:to="mrcy_SeniorUnsecuredCreditFacilitiesMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_SeveranceMember" xlink:label="mrcy_SeveranceMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_SeveranceMember_lbl" xml:lang="en-US" id="id_1835722_581818_3_1">Severance [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_SeveranceMember_lbl" xml:lang="en-US" id="id_1835722_581818_1_1">Severance [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_SeveranceMember_lbl" xml:lang="en-US" id="id_1835722_581818_2_1">Severance</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_SeveranceMember" xlink:to="mrcy_SeveranceMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="us-gaap_ShareBasedCompensation"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensation_lbl" xml:lang="en-US" id="id_1835722_501410_1_1">Share Based Compensation</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensation_lbl" xml:lang="en-US" id="id_1835722_501410_2_1">Share-based compensation expense before tax</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ShareBasedCompensation_lbl" xml:lang="en-US" id="id_1835722_501410_12_1">Stock-based compensation expense</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensation" xlink:to="us-gaap_ShareBasedCompensation_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_lbl" xml:lang="en-US" id="id_1835722_510571_1_1">Share Based Compensation Arrangement By Share Based Payment Award Award Requisite Service Period 1</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_lbl" xml:lang="en-US" id="id_1835722_510571_2_1">Options, vesting period</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_ShareBasedCompensationArrangementByShareBasedPaymentAwardContractualLife" xlink:label="mrcy_ShareBasedCompensationArrangementByShareBasedPaymentAwardContractualLife"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_ShareBasedCompensationArrangementByShareBasedPaymentAwardContractualLife_lbl" xml:lang="en-US" id="id_1835722_529969_3_1">Maximum number of years for the company's stock options before they expire.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_ShareBasedCompensationArrangementByShareBasedPaymentAwardContractualLife_lbl" xml:lang="en-US" id="id_1835722_529969_1_1">Share Based Compensation Arrangement By Share Based Payment Award Contractual Life</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_ShareBasedCompensationArrangementByShareBasedPaymentAwardContractualLife_lbl" xml:lang="en-US" id="id_1835722_529969_2_1">Term of stock option</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_ShareBasedCompensationArrangementByShareBasedPaymentAwardContractualLife" xlink:to="mrcy_ShareBasedCompensationArrangementByShareBasedPaymentAwardContractualLife_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate_lbl" xml:lang="en-US" id="id_1835722_508680_1_1">Share Based Compensation Arrangement By Share Based Payment Award Discount From Market Price Offering Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate_lbl" xml:lang="en-US" id="id_1835722_508680_2_1">Purchase price as a percentage of the lesser of the market value of such shares at either the beginning or the end of each nine-month offering period</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl" xml:lang="en-US" id="id_1835722_514454_1_1">Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeited In Period</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl" xml:lang="en-US" id="id_1835722_514454_8_1">Forfeited</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US" id="id_1835722_509892_1_1">Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeitures Weighted Average Grant Date Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US" id="id_1835722_509892_2_1">Forfeited</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xml:lang="en-US" id="id_1835722_500719_1_1">Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xml:lang="en-US" id="id_1835722_500719_2_1">Granted</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US" id="id_1835722_507062_1_1">Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Weighted Average Grant Date Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US" id="id_1835722_507062_2_1">Granted</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xml:lang="en-US" id="id_1835722_510998_1_1">Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xml:lang="en-US" id="id_1835722_510998_4_1">Ending Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xml:lang="en-US" id="id_1835722_510998_5_1">Beginning Balance</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_lbl" xml:lang="en-US" id="id_1835722_507412_1_1">Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested [Roll Forward]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_lbl" xml:lang="en-US" id="id_1835722_507412_2_1">Number of Shares</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US" id="id_1835722_506728_1_1">Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_lbl" xml:lang="en-US" id="id_1835722_500585_1_1">Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Rollforward</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract_lbl" xml:lang="en-US" id="id_1835722_518607_3_1">Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Remaining Contractual Term [Abstract]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xml:lang="en-US" id="id_1835722_499605_2_1">Award Type [Domain]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_1835722_505372_1_1">Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_1835722_501417_1_1">Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US" id="id_1835722_501417_2_1">Granted</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_SignificantAccountingPoliciesLineItems_lbl" xml:lang="en-US" id="id_1835722_518720_3_1">Significant Accounting Policies [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_SignificantAccountingPoliciesLineItems_lbl" xml:lang="en-US" id="id_1835722_518720_1_1">Significant Accounting Policies [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_SignificantAccountingPoliciesLineItems_lbl" xml:lang="en-US" id="id_1835722_518720_2_1">Significant Accounting Policies [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_SignificantAccountingPoliciesLineItems" xlink:to="mrcy_SignificantAccountingPoliciesLineItems_lbl"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_SignificantAccountingPoliciesTable_lbl" xml:lang="en-US" id="id_1835722_541657_3_1">Significant Accounting Policies [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_SignificantAccountingPoliciesTable_lbl" xml:lang="en-US" id="id_1835722_541657_1_1">Significant Accounting Policies [Table]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_SignificantAccountingPoliciesTable" xlink:to="mrcy_SignificantAccountingPoliciesTable_lbl"/>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SignificantPurchaseCommitmentRemainingMinimumAmountCommitted" xlink:label="us-gaap_SignificantPurchaseCommitmentRemainingMinimumAmountCommitted"/>
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    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_SiliconValleyBankLoanAndSecurityAgreementMember" xlink:label="mrcy_SiliconValleyBankLoanAndSecurityAgreementMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_SiliconValleyBankLoanAndSecurityAgreementMember_lbl" xml:lang="en-US" id="id_1835722_557818_3_1">Silicon Valley Bank Loan And Security Agreement [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_SiliconValleyBankLoanAndSecurityAgreementMember_lbl" xml:lang="en-US" id="id_1835722_557818_1_1">Silicon Valley Bank Loan And Security Agreement [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_SiliconValleyBankLoanAndSecurityAgreementMember_lbl" xml:lang="en-US" id="id_1835722_557818_2_1">Loan and Security Agreement with Silicon Valley Bank</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StatementLineItems_lbl" xml:lang="en-US" id="id_1835722_507536_2_1">Statement [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="us-gaap_StatementOfCashFlowsAbstract"/>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_StatementSegmentReportingAxis_lbl" xml:lang="en-US" id="id_1835722_549340_1_1">Statement Segment Reporting [Axis]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_StatementSegmentReportingAxis_lbl" xml:lang="en-US" id="id_1835722_549340_2_1">Statement Segment Reporting [Axis]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_StatementSegmentReportingDomain_lbl" xml:lang="en-US" id="id_1835722_549571_3_1">Statement Segment Reporting [Domain]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xml:lang="en-US" id="id_1835722_498963_1_1">Stockholders Equity [Abstract]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssued1" xlink:label="us-gaap_StockIssued1"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssued1_lbl" xml:lang="en-US" id="id_1835722_503316_1_1">Stock Issued 1</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssued1_lbl" xml:lang="en-US" id="id_1835722_503316_2_1">Issuance of restricted stock awards to employees</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xml:lang="en-US" id="id_1835722_502579_1_1">Stock Issued During Period Shares Stock Options Exercised</label>
    <label xlink:type="resource" xlink:role="http://xbrl.us/us-gaap/role/label/negated" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xml:lang="en-US" id="id_1835722_502579_8_1">Exercised</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_StockOptionPlanNineteenNinetySevenMember" xlink:label="mrcy_StockOptionPlanNineteenNinetySevenMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_StockOptionPlanNineteenNinetySevenMember_lbl" xml:lang="en-US" id="id_1835722_515872_3_1">Stock Option Plan 1997 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_StockOptionPlanNineteenNinetySevenMember_lbl" xml:lang="en-US" id="id_1835722_515872_1_1">Stock Option Plan Nineteen Ninety Seven [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_StockOptionPlanNineteenNinetySevenMember_lbl" xml:lang="en-US" id="id_1835722_515872_2_1">Stock Option Plan 1997</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_StockOptionPlanNineteenNinetySevenMember" xlink:to="mrcy_StockOptionPlanNineteenNinetySevenMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_StockOptionPlanTwentyZeroFiveMember" xlink:label="mrcy_StockOptionPlanTwentyZeroFiveMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_StockOptionPlanTwentyZeroFiveMember_lbl" xml:lang="en-US" id="id_1835722_544952_3_1">Stock Option Plan, Twenty Zero Five [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_StockOptionPlanTwentyZeroFiveMember_lbl" xml:lang="en-US" id="id_1835722_544952_1_1">Stock Option Plan Twenty Zero Five [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_StockOptionPlanTwentyZeroFiveMember_lbl" xml:lang="en-US" id="id_1835722_544952_2_1">2005 Stock Incentive Plan</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_StockOptionPlanTwentyZeroFiveMember" xlink:to="mrcy_StockOptionPlanTwentyZeroFiveMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="us-gaap_StockOptionsMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockOptionsMember_lbl" xml:lang="en-US" id="id_1835722_514283_1_1">Stock Options [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockOptionsMember_lbl" xml:lang="en-US" id="id_1835722_514283_2_1">Stock Options</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockOptionsMember" xlink:to="us-gaap_StockOptionsMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SubsequentEventsAbstract" xlink:label="us-gaap_SubsequentEventsAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SubsequentEventsAbstract_lbl" xml:lang="en-US" id="id_1835722_510199_1_1">Subsequent Events [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SubsequentEventsAbstract_lbl" xml:lang="en-US" id="id_1835722_510199_2_1">Subsequent Events [Abstract]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsequentEventsAbstract" xlink:to="us-gaap_SubsequentEventsAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SubsequentEventsTextBlock" xlink:label="us-gaap_SubsequentEventsTextBlock"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SubsequentEventsTextBlock_lbl" xml:lang="en-US" id="id_1835722_507047_1_1">Subsequent Events [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SubsequentEventsTextBlock_lbl" xml:lang="en-US" id="id_1835722_507047_2_1">Subsequent Events</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsequentEventsTextBlock" xlink:to="us-gaap_SubsequentEventsTextBlock_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xml:lang="en-US" id="id_1835722_498644_1_1">Supplemental Cash Flow Information [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xml:lang="en-US" id="id_1835722_498644_2_1">Cash paid (received) during the period for:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="us-gaap_SupplementalCashFlowInformationAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TaxCreditCarryforwardLineItems" xlink:label="us-gaap_TaxCreditCarryforwardLineItems"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TaxCreditCarryforwardLineItems_lbl" xml:lang="en-US" id="id_1835722_512295_1_1">Tax Credit Carryforward [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TaxCreditCarryforwardLineItems_lbl" xml:lang="en-US" id="id_1835722_512295_2_1">Tax Credit Carryforward [Line Items]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TaxCreditCarryforwardLineItems" xlink:to="us-gaap_TaxCreditCarryforwardLineItems_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TaxCreditCarryforwardTable" xlink:label="us-gaap_TaxCreditCarryforwardTable"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TaxCreditCarryforwardTable_lbl" xml:lang="en-US" id="id_1835722_508624_1_1">Tax Credit Carryforward [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TaxCreditCarryforwardTable_lbl" xml:lang="en-US" id="id_1835722_508624_2_1">Tax Credit Carryforward [Table]</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TaxCreditCarryforwardTable" xlink:to="us-gaap_TaxCreditCarryforwardTable_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TrademarksMember" xlink:label="us-gaap_TrademarksMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TrademarksMember_lbl" xml:lang="en-US" id="id_1835722_512398_1_1">Trademarks [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TrademarksMember_lbl" xml:lang="en-US" id="id_1835722_512398_2_1">Trademarks</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TrademarksMember" xlink:to="us-gaap_TrademarksMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_TradingSymbol" xlink:label="dei_TradingSymbol"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="dei_TradingSymbol_lbl" xml:lang="en-US" id="id_1835722_497703_1_1">Trading Symbol</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="dei_TradingSymbol_lbl" xml:lang="en-US" id="id_1835722_497703_2_1">Trading Symbol</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_TradingSymbol" xlink:to="dei_TradingSymbol_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_TwentyTwelveRestructuringPlanMember" xlink:label="mrcy_TwentyTwelveRestructuringPlanMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_TwentyTwelveRestructuringPlanMember_lbl" xml:lang="en-US" id="id_1835722_675047_3_1">Twenty Twelve Restructuring Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_TwentyTwelveRestructuringPlanMember_lbl" xml:lang="en-US" id="id_1835722_675047_1_1">Twenty Twelve Restructuring Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_TwentyTwelveRestructuringPlanMember_lbl" xml:lang="en-US" id="id_1835722_675047_2_1">2012 Restructuring Plan</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_TwentyTwelveRestructuringPlanMember" xlink:to="mrcy_TwentyTwelveRestructuringPlanMember_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2012/country-2012-01-31.xsd#country_US" xlink:label="country_US"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="country_US_lbl" xml:lang="en-US" id="id_1835722_497488_1_1">U S</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="country_US_lbl" xml:lang="en-US" id="id_1835722_497488_2_1">US</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="country_US" xlink:to="country_US_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_UseOfEstimates" xlink:label="us-gaap_UseOfEstimates"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_UseOfEstimates_lbl" xml:lang="en-US" id="id_1835722_513922_1_1">Use Of Estimates</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_UseOfEstimates_lbl" xml:lang="en-US" id="id_1835722_513922_2_1">Use of Estimates</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UseOfEstimates" xlink:to="us-gaap_UseOfEstimates_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_USTreasuryBillSecuritiesMember" xlink:label="us-gaap_USTreasuryBillSecuritiesMember"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_USTreasuryBillSecuritiesMember_lbl" xml:lang="en-US" id="id_1835722_498704_1_1">U S Treasury Bill Securities [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_USTreasuryBillSecuritiesMember_lbl" xml:lang="en-US" id="id_1835722_498704_2_1">U.S. Treasury bills and money market funds</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_USTreasuryBillSecuritiesMember" xlink:to="us-gaap_USTreasuryBillSecuritiesMember_lbl"/>
    <loc xlink:type="locator" xlink:href="mrcy-20130331.xsd#mrcy_WeightedAverageNumberBasicAndDilutedSharesOutstandingAbstract" xlink:label="mrcy_WeightedAverageNumberBasicAndDilutedSharesOutstandingAbstract"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="mrcy_WeightedAverageNumberBasicAndDilutedSharesOutstandingAbstract_lbl" xml:lang="en-US" id="id_1835722_518661_3_1">Weighted Average Number Basic And Diluted, Shares Outstanding [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="mrcy_WeightedAverageNumberBasicAndDilutedSharesOutstandingAbstract_lbl" xml:lang="en-US" id="id_1835722_518661_1_1">Weighted Average Number Basic And Diluted Shares Outstanding [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="mrcy_WeightedAverageNumberBasicAndDilutedSharesOutstandingAbstract_lbl" xml:lang="en-US" id="id_1835722_518661_2_1">Weighted-average shares outstanding:</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="mrcy_WeightedAverageNumberBasicAndDilutedSharesOutstandingAbstract" xlink:to="mrcy_WeightedAverageNumberBasicAndDilutedSharesOutstandingAbstract_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xml:lang="en-US" id="id_1835722_510509_1_1">Weighted Average Number Diluted Shares Outstanding Adjustment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xml:lang="en-US" id="id_1835722_510509_2_1">Effect of dilutive equity instruments</label>
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:to="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xml:lang="en-US" id="id_1835722_507210_1_1">Weighted Average Number Of Diluted Shares Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xml:lang="en-US" id="id_1835722_507210_2_1">Diluted</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xml:lang="en-US" id="id_1835722_507210_6_1">Diluted weighted-average shares outstanding</label>
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