<SUBMISSION>
<ACCESSION-NUMBER>0001186656-04-000001
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20031231
<FILING-DATE>20040107
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>SCHMINKEY GARY R
<CIK>0001186656
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-20288
<FILM-NUMBER>04513956
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>1301 A STREET
<STREET2>MS 3100
<CITY>TACOMA
<STATE>WA
<ZIP>98402-4200
</BUSINESS-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>COLUMBIA BANKING SYSTEM INC
<CIK>0000887343
<ASSIGNED-SIC>6022
<IRS-NUMBER>911422237
<STATE-OF-INCORPORATION>WA
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>1102 BROADWAY PLAZA
<CITY>TACOMA
<STATE>WA
<ZIP>98402
<PHONE>2533051900
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>1102 BROADWAY PLAZA
<CITY>TACOMA
<STATE>WA
<ZIP>98402
</MAIL-ADDRESS>
</ISSUER>
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<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
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<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

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    <issuer>
        <issuerCik>0000887343</issuerCik>
        <issuerName>COLUMBIA BANKING SYSTEM INC</issuerName>
        <issuerTradingSymbol>COLB</issuerTradingSymbol></issuer><reportingOwner>
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            <rptOwnerCik>0001186656</rptOwnerCik>
            <rptOwnerName>SCHMINKEY GARY R</rptOwnerName>
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        <reportingOwnerAddress>
            <rptOwnerStreet1>1301 A STREET, STE. 800</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>TACOMA</rptOwnerCity>
            <rptOwnerState>WA</rptOwnerState>
            <rptOwnerZipCode>98402-4200</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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