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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 VYHS96trdEPG1et9IhOrRufu2Lur5zW7V0pay1tCSz0vHJs/sbP1iGjuJaiyAyrc
 vzeUdMDk2CarMYkIWMd8kw==

<SEC-DOCUMENT>0001181431-10-042794.txt : 20100820
<SEC-HEADER>0001181431-10-042794.hdr.sgml : 20100820
<ACCEPTANCE-DATETIME>20100820123627
ACCESSION NUMBER:		0001181431-10-042794
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100820
FILED AS OF DATE:		20100820
DATE AS OF CHANGE:		20100820

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SALINE CRAIG A
		CENTRAL INDEX KEY:			0001274409

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23599
		FILM NUMBER:		101029590

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MERCURY COMPUTER SYSTEMS INC
		CENTRAL INDEX KEY:			0001049521
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRONIC COMPONENTS & ACCESSORIES [3670]
		IRS NUMBER:				042741391
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		201 RIVERNECK ROAD
		CITY:			CHELMSFORD
		STATE:			MA
		ZIP:			01824
		BUSINESS PHONE:		9782561300

	MAIL ADDRESS:	
		STREET 1:		201 RIVERNECK ROAD
		CITY:			CHELMSFORD
		STATE:			MA
		ZIP:			01824
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>rrd284448.xml
<DESCRIPTION>AMEND BENEFICIAL OWNERSHIP
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2010-08-20</periodOfReport>

    <dateOfOriginalSubmission>2010-08-17</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001049521</issuerCik>
        <issuerName>MERCURY COMPUTER SYSTEMS INC</issuerName>
        <issuerTradingSymbol>MRCY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001274409</rptOwnerCik>
            <rptOwnerName>SALINE CRAIG A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>201 RIVERNECK ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHELMSFORD</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01824</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP, Human Resources</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>43607</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The purpose of this amended Form 4 is to amend Mr. Saline's beneficial ownership.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Craig Saline</signatureName>
        <signatureDate>2010-08-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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