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

    <documentType>4</documentType><periodOfReport>2003-12-15</periodOfReport>
    <issuer>
        <issuerCik>0000002135</issuerCik>
        <issuerName>AFFILIATED COMPUTER SERVICES INC</issuerName>
        <issuerTradingSymbol>ACS</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001182592</rptOwnerCik>
            <rptOwnerName>RICH JEFFREY A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2828 N. HASKELL AVENUE, BLDG. 1, FL-10</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75204</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Chief Executive Officer</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Class A Common Stock par value $0.01</value></securityTitle><transactionDate><value>2003-12-15</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>48100</value></transactionShares><transactionPricePerShare><value>10.5625</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>139072</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>Class A Common Stock par value $0.01</value></securityTitle><transactionDate><value>2003-12-15</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>48100</value></transactionShares><transactionPricePerShare><value>53.242</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>90972</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeHolding><securityTitle><value>Class A Common Stock par value $0.01</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>992</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>ESP Plan</value></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeHolding><securityTitle><value>Class A Common Stock $0.01 par value</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>360</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>401k Plan</value></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Employee Stock Option (Right to Buy)</value></securityTitle><conversionOrExercisePrice><value>10.5625</value></conversionOrExercisePrice><transactionDate><value>2003-12-15</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>48100</value></transactionShares><transactionPricePerShare><value>53.242</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2002-04-07</value></exerciseDate><expirationDate><value>2007-04-07</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>48100</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>11.5312</value></conversionOrExercisePrice><exerciseDate><value>2003-10-08</value></exerciseDate><expirationDate><value>2008-10-08</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>500000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>500000</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>16.4375</value></conversionOrExercisePrice><exerciseDate><value>2005-07-11</value></exerciseDate><expirationDate><value>2010-07-11</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>200000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>700000</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</value></underlyingSecurityTitle><underlyingSecurityShares><value>400000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1100000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes/><remarks/><ownerSignature><signatureName>Jeffrey A. Rich</signatureName><signatureDate>2003-12-15</signatureDate></ownerSignature></ownershipDocument>

