-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 PW1oLITBUQO6k1ArMyvUj6uEvsTpc57ww2gDpOT6v4wo0ltEE67yG+qS+0uOys/R
 X74M5a2NvGCZW3RN8ta6QQ==

<SEC-DOCUMENT>0000866273-05-000004.txt : 20050408
<SEC-HEADER>0000866273-05-000004.hdr.sgml : 20050408
<ACCEPTANCE-DATETIME>20050408164229
ACCESSION NUMBER:		0000866273-05-000004
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050406
FILED AS OF DATE:		20050408
DATE AS OF CHANGE:		20050408

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LACKEY PAUL K
		CENTRAL INDEX KEY:			0001192252

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-15461
		FILM NUMBER:		05741952

	BUSINESS ADDRESS:	
		STREET 1:		10701 E UTE
		CITY:			TULSA
		STATE:			OK
		ZIP:			74116
		BUSINESS PHONE:		9188388822

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MATRIX SERVICE CO
		CENTRAL INDEX KEY:			0000866273
		STANDARD INDUSTRIAL CLASSIFICATION:	CONSTRUCTION SPECIAL TRADE CONTRACTORS [1700]
		IRS NUMBER:				731352174
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0531

	BUSINESS ADDRESS:	
		STREET 1:		10701 E UTE ST
		CITY:			TULSA
		STATE:			OK
		ZIP:			74116-1517
		BUSINESS PHONE:		9188388822

	MAIL ADDRESS:	
		STREET 1:		10701 E UTE ST
		CITY:			TULSA
		STATE:			OK
		ZIP:			74116-1517
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-04-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000866273</issuerCik>
        <issuerName>MATRIX SERVICE CO</issuerName>
        <issuerTradingSymbol>MTRX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001192252</rptOwnerCik>
            <rptOwnerName>LACKEY PAUL K</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>4502 EAST 41ST STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 3B33</rptOwnerStreet2>
            <rptOwnerCity>TULSA</rptOwnerCity>
            <rptOwnerState>OK</rptOwnerState>
            <rptOwnerZipCode>74135</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Shares</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-04-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2083</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2083</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>18027</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Matrix Service Company Common Stock</footnote>
        <footnote id="F2">Not applicable</footnote>
        <footnote id="F3">The SAR became 100% exercisable upon grant.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Paul K. Lackey</signatureName>
        <signatureDate>2005-04-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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