<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-07-18</periodOfReport>
    <issuer>
        <issuerCik>0000723188</issuerCik>
        <issuerName>COMMUNITY BANK SYSTEM INC</issuerName>
        <issuerTradingSymbol>CBU</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId>
            <rptOwnerCik>0001233262</rptOwnerCik>
            <rptOwnerName>WEARS JAMES A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>President/Banking</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-07-18</value></transactionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>G</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>200</value></transactionShares><transactionValue><value>0</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>200</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>by daughter, Julia</value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><footnotes><footnote id="F1">Does not include 16,649.0777 shares held directly by the reporting person; 699.9994 shares held indirectly by spouse; 19,002.9137 shares held indirectly through a 401(k) plan (which information is based on a plan statement dated as of December 31, 2002); 1,000.564 shares held indirectly by son, Daniel; and 837.481 shares held indirectly by son, Thomas.  The reporting person no longer has a reportable beneficial interest in 496.708 shares owned by his daughter, Katherine, and included in the reporting person's prior ownership reports.</footnote></footnotes><ownerSignature><signatureName>Donna J. Drengel, attorney-in-fact, pursuant to a power of attorney</signatureName><signatureDate>2003-07-21</signatureDate></ownerSignature></ownershipDocument>

