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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-09-04</periodOfReport>

    <issuer>
        <issuerCik>0000857644</issuerCik>
        <issuerName>TEPPCO PARTNERS LP</issuerName>
        <issuerTradingSymbol>TPP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001353566</rptOwnerCik>
            <rptOwnerName>BROWN SAMUEL N</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1100 LOUISIANA STREET; SUITE 1600</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77002</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Units Representing Limited Partnership Interests</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6400</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Class B Limited Partnership Interest in TEPPCO Unit L.P.</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-09-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>0</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Units</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <footnoteId id="F3"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Includes common units granted to the Reporting Person that have restricted vesting dates and are subject to forfeiture.</footnote>
        <footnote id="F2">The reporting person is an owner of Class B limited partner interest in TEPPCO Unit L.P. (&quot;TEPPCO Unit&quot;). TEPPCO Unit owns directly 241,380 Units of TEPPCO Partners, L.P. (&quot;TEPPCO&quot;). TEPPCO Unit is a Delaware limited partnership established for the benefit of certain EPCO, Inc. &quot;EPCO&quot;) employees who are its Class B limited partners. EPCO Holdings, Inc. (&quot;EPCO Holdings&quot;) is the sole Class A limited partner and EPCO is the general partner of TEPPCO Unit. The reporting person acquired these Class B limited partner interests in TEPPCO Unit from a grant of such interests by EPCO, in its capacity as general partner of TEPPCO Unit. The Class B limited partner interest owned by the reporting person represent an initial 14.28571% Class B limited partner interest in TEPPCO Unit, in accordance with the Agreement of Limited Partnership of TEPPCO Unit.</footnote>
        <footnote id="F3">On September 4, 2013, TEPPCO Unit will be liquidated and will distribute to the Class B Limited Partners a total number of Units equal to (i) approximately 241,380 minus (ii) the quotient of (a) $7,000,000 plus any undistributed preferred return to the Class A Limited Partner divided by (b) the fair market value (as defined) of the Units calculated as of September 4, 2013. The remaining Units will be distributed to EPCO Holdings as the Class A Limited Partner. The Class B limited partner interest is subject to forfeiture.</footnote>
        <footnote id="F4">The power of attorney under which this form was signed is on file with the Commission.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Vickie L. Graham, Attorney-in-Fact on behalf of Samuel N. Brown</signatureName>
        <signatureDate>2008-09-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
