<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-06-07</periodOfReport>

    <issuer>
        <issuerCik>0000945114</issuerCik>
        <issuerName>SYSTEMAX INC</issuerName>
        <issuerTradingSymbol>SYX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001243720</rptOwnerCik>
            <rptOwnerName>DICK STACY S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SYSTEMAX INC.</rptOwnerStreet1>
            <rptOwnerStreet2>11 HARBOR PARK DRIVE</rptOwnerStreet2>
            <rptOwnerCity>PORT WASHINGTON</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>11050</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>2007-06-07</value>
                <footnoteId id="F1"/>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1300</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3427</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On June 7, 2007, the reporting person received 1,300 shares of restricted stock pursuant to the Company's 2006 Stock Incentive Plan For Non-Employee Directors. Pursuant to the plan, such number of restricted shares was determined by dividing $25,000 by the closing price per share during the 20 trading days preceding the date of such meeting (rounded up to the nearest whole number of shares). Such shares are generally subject to forfeiture if the holder is not a director of the company on the second anniversary of grant, and can not be sold while so restricted; such restrictions lapse if the holder dies or becomes disabled or there is a change of control, as defined in the plan.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Stacy Dick, by Curt Rush, attorney-in-fact</signatureName>
        <signatureDate>2007-06-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
