<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-12-29</periodOfReport>
    <issuer>
        <issuerCik>0000002135</issuerCik>
        <issuerName>AFFILIATED COMPUTER SERVICES INC</issuerName>
        <issuerTradingSymbol>ACS</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001079719</rptOwnerCik>
            <rptOwnerName>DEASON DARWIN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2828 N. HASKELL AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75204</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>1</isTenPercentOwner><isOther>0</isOther><officerTitle>Chairman of the Board</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>Class A Common Stock $0.01 par value</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>2588194</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeHolding><securityTitle><value>Class B Common Stock $0.01 par value</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>6599372</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeHolding><securityTitle><value>Class A Common Stock $0.01 par value</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5214</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>ESP Plan</value></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Call Options (obligation to sell)</value><footnoteId id="F1"/></securityTitle><conversionOrExercisePrice><value>60.00</value></conversionOrExercisePrice><transactionDate><value>2003-12-29</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F2"/></transactionCoding><transactionAmounts><transactionShares><value>500</value></transactionShares><transactionPricePerShare><value>180.00</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2003-12-29</value></exerciseDate><expirationDate><value>2004-07-09</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>50000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeHolding><securityTitle><value>Employee Stock Option (Right to Buy)</value></securityTitle><conversionOrExercisePrice><value>44.10</value></conversionOrExercisePrice><exerciseDate><value>2007-07-01</value><footnoteId id="F3"/></exerciseDate><expirationDate><value>2013-08-11</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>300000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1050000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee Stock Option (Right to Buy)</value></securityTitle><conversionOrExercisePrice><value>35.75</value></conversionOrExercisePrice><exerciseDate><value>2007-07-23</value></exerciseDate><expirationDate><value>2012-07-23</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>600000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>750000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee Stock Option (Right to Buy)</value></securityTitle><conversionOrExercisePrice><value>11.5312</value></conversionOrExercisePrice><exerciseDate><value>2007-07-01</value><footnoteId id="F3"/></exerciseDate><expirationDate><value>2008-10-08</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>150000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>150000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">From December 17, 2003 to December 24, 2003, the reporting person wrote 2,300 call options (obligation to sell) for a total of 230,000 shares of Class A Common Stock at an exercise price of $60.00 per share expiring July 9, 2004.</footnote><footnote id="F2">The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 15, 2003.</footnote><footnote id="F3">This stock option grant is related to reporting person's Supplemental Executive Retirement Agreement, as amended (&quot;SERP&quot;).  This option is currently exercisable on reporting person's normal retirement date under the terms of the SERP, but subject to change based on the occurrence of certain designated events.</footnote></footnotes><remarks/><ownerSignature><signatureName>Darwin Deason</signatureName><signatureDate>2003-12-29</signatureDate></ownerSignature></ownershipDocument>

