<?xml version="1.0"?><ownershipDocument><schemaVersion>X0201</schemaVersion>    <documentType>4</documentType><periodOfReport>2003-12-18</periodOfReport><notSubjectToSection16>1</notSubjectToSection16><issuer><issuerCik>0000930885</issuerCik><issuerName>DOCUMENTUM INC</issuerName>        <issuerTradingSymbol>DCTM</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001237887</rptOwnerCik><rptOwnerName>ADAMS ROBERT V</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>6801 KOLL CENTER PARKWAY</rptOwnerStreet1><rptOwnerStreet2></rptOwnerStreet2><rptOwnerCity>PLEASANTON</rptOwnerCity><rptOwnerState>CA</rptOwnerState><rptOwnerZipCode>94566-7047</rptOwnerZipCode><rptOwnerStateDescription></rptOwnerStateDescription></reportingOwnerAddress><reportingOwnerRelationship><isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Stock`</value></securityTitle><transactionDate><value>2003-12-18</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>5000.0000</value></transactionShares><transactionPricePerShare><value>12.0000</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>95172.0000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-12-18</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>10000.0000</value></transactionShares><transactionPricePerShare><value>19.5900</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>105172.0000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-12-18</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>D</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>105172.0000</value></transactionShares><transactionPricePerShare><value>0</value><footnoteId id="F1" /></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></nonDerivativeTransaction></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Option to Buy Common Stock</value></securityTitle><conversionOrExercisePrice><value>12.0000</value></conversionOrExercisePrice><transactionDate><value>2003-12-18</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>5000.0000</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2002-06-30</value><footnoteId id="F2" /></exerciseDate><expirationDate><value>2012-06-30</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>5000.0000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>Option to Buy Common Stock</value></securityTitle><conversionOrExercisePrice><value>19.5900</value></conversionOrExercisePrice><transactionDate><value>2003-12-18</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>10000.0000</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2003-06-30</value><footnoteId id="F2" /></exerciseDate><expirationDate><value>2013-06-30</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>10000.0000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>Option to Buy Common Stock</value></securityTitle><conversionOrExercisePrice><value>35.0000</value></conversionOrExercisePrice><transactionDate><value>2003-12-18</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>D</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>20000.0000</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2000-02-09</value><footnoteId id="F3" /></exerciseDate><expirationDate><value>2010-02-09</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>20000.0000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">Disposed of pursuant to merger agreement between issuer and EMC Corporation in exchange for (i) 228,749 shares of EMC common stock having a market value of $12.85 per share on effective date of merger plus (ii) approximately $1.29 of cash in lieu for fractional share.</footnote><footnote id="F2">This option was granted under the Documentum Inc. 1995 Non-Employee Directors' Stock Option Plan.  The option was exercisable immediately as to one-third of the shares and thereafter become exercisable in two equal annual installments.  Any unvested shares at the closing of the merger with EMC Corporation became immediately exercisable.</footnote><footnote id="F3">This option which was granted under the Company's 1993 Equity Incentive Plan was immediately exercisable upon grant date and was assumed by EMC in the merger and replaced with an option to purchase 43,500 shares of EMC common stock for $16.10 per share.</footnote></footnotes><remarks></remarks><ownerSignature><signatureName>JoAnne Zinman as Attorney in Fact for Robert V. Adams</signatureName><signatureDate>2003-12-22</signatureDate></ownerSignature></ownershipDocument>

