-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 WhheHdXG1nVljWQpPhbHNA+5oHBJnCtOYcLpeJA4QQG0srk5bFA30KU3YuAKmkZj
 c5UyC6NJMLRKpyrxH/3XcQ==

<SEC-DOCUMENT>0001181431-04-034366.txt : 20040707
<SEC-HEADER>0001181431-04-034366.hdr.sgml : 20040707
<ACCEPTANCE-DATETIME>20040707105332
ACCESSION NUMBER:		0001181431-04-034366
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040628
FILED AS OF DATE:		20040707

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:		199 RIVERNECK RD
		CITY:			CHELMSFORD
		STATE:			MA
		ZIP:			01824
		BUSINESS PHONE:		9782561300

	MAIL ADDRESS:	
		STREET 1:		199 RIVERNECK ROAD
		CITY:			CHELMSFORD
		STATE:			MA
		ZIP:			01824

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CHAMILLARD GEORGE W
		CENTRAL INDEX KEY:			0001192442

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23599
		FILM NUMBER:		04903706

	BUSINESS ADDRESS:	
		STREET 1:		C/O VARIAN SEMICONDUCTOR EQUIPMENT
		STREET 2:		35 DORY ROAD
		CITY:			GLOUCESTER
		STATE:			MA
		ZIP:			01930
		BUSINESS PHONE:		6174223038

	MAIL ADDRESS:	
		STREET 1:		321 HARRISON AVENUE
		STREET 2:		C/O TERADYNE INC
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02118
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>rrd46666.xml
<DESCRIPTION>INITIAL FILING
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2004-06-28</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001192442</rptOwnerCik>
            <rptOwnerName>CHAMILLARD GEORGE W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>MERCURY COMPUTER SYSTEMS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>199 RIVERNECK ROAD</rptOwnerStreet2>
            <rptOwnerCity>CHELMSFORD</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01824</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>No Securities Beneficially Owned</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>Joseph M. Hartnett, Attorney-in-fact</signatureName>
        <signatureDate>2004-07-07</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----