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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-03-22</periodOfReport>

    <issuer>
        <issuerCik>0000735571</issuerCik>
        <issuerName>WARRANTECH CORP</issuerName>
        <issuerTradingSymbol>WTEC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001315057</rptOwnerCik>
            <rptOwnerName>Senderowitz Donald</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WARRANTECH CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>2200 HIGHWAY 121</rptOwnerStreet2>
            <rptOwnerCity>BEDFORD</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76021</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>2005-03-22</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>7500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>.60</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>29700</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks>(1)   Received as a portion of a quarterly fee for serving as a director of the Issuer and on committees of the Issuer's Board of Directors.
(2)  Transaction previously reported.
(3)   Such shares are owned by a Uniform Gift to Minors Act accounts for the benefit of one of the Reporting Person's minor son.  The Reporting Person's wife, Mindy Richenstein, is the custodian of the account, and, accordingly, the Reporting Person may be deemed to have an indirect pecuniary interest therein.  The Reporting Person expressly disclaims beneficial ownership of these shares for the purpose of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise.</remarks>

    <ownerSignature>
        <signatureName>Donald Senderowitz</signatureName>
        <signatureDate>2005-03-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
