<SUBMISSION>
<ACCESSION-NUMBER>0001179110-05-019379
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20051005
<FILING-DATE>20051006
<DATE-OF-FILING-DATE-CHANGE>20051006
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>OVERSTOCK COM INC
<CIK>0001130713
<ASSIGNED-SIC>5961
<IRS-NUMBER>870634302
<STATE-OF-INCORPORATION>UT
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>6322 SOUTH 3000 EAST
<STREET2>STE 100
<CITY>SALT LAKE CITY
<STATE>UT
<ZIP>84121
<PHONE>8019473100
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>6322 SOUTH 3000 EAST
<STREET2>STE 100
<CITY>SALT LAKE CITY
<STATE>UT
<ZIP>84121
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>BYRNE JOHN JOSEPH
<CIK>0001181359
<ASSIGNED-SIC>6331
<STATE-OF-INCORPORATION>D0
<FISCAL-YEAR-END>1231
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-49799
<FILM-NUMBER>051126530
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>C/O WHITE MOUNTAINS INSURANCE GROUP, LTD
<STREET2>80 SOUTH MAIN STREET
<CITY>HANOVER
<STATE>NH
<ZIP>03755
<PHONE>6036402200
</BUSINESS-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-10-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001130713</issuerCik>
        <issuerName>OVERSTOCK COM INC</issuerName>
        <issuerTradingSymbol>OSTK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001181359</rptOwnerCik>
            <rptOwnerName>BYRNE JOHN JOSEPH</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>6350 SOUTH 3000 EAST</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SALT LAKE CITY</rptOwnerCity>
            <rptOwnerState>UT</rptOwnerState>
            <rptOwnerZipCode>84121</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>266559</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by High Meadows Finance, L.C.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>49929</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by spouse.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>415468</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by Haverford Utah, L.L.C.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>306364</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by Jack Byrne 2004 GRAT No. 1.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>237181</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by Jack Byrne 2005 GRAT No. 1.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">On October 4, 2005, High Meadows Finance, L.C. distributed 201,693 shares of the issuer pro rata to its owners, including the reporting person.  The reporting person had previously reported indirect beneficial ownership of all such 201,693 shares.  The pro rata distribution of the shares effected only a change in the reporting person's form of beneficial ownership, and did not increase or decrease the reporting person's pecuniary interest in the shares or transfer a pecuniary interest in the shares to another person.  For purposes of clarity, the reporting person is voluntarily filing this report to note the 201,693 share decrease in his indirect beneficial ownership and the 66,559 share increase in his direct beneficial ownership resulting from the pro rata distribution.</footnote>
        <footnote id="F2">The reporting person disclaims beneficial ownership of these securities, except to the extent of his pecuniary ownership therein, and this report shall not be deemed an admission that the reporting person is the beneficial owner of the securities for purposes of Section 16 or any other purpose.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ John J. Byrne</signatureName>
        <signatureDate>2005-10-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
