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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-10-27</periodOfReport>

    <issuer>
        <issuerCik>0000106926</issuerCik>
        <issuerName>WHITNEY HOLDING CORP</issuerName>
        <issuerTradingSymbol>WTNY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001453842</rptOwnerCik>
            <rptOwnerName>Cowell Elizabeth L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>228 ST. CHARLES AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW ORLEANS</rptOwnerCity>
            <rptOwnerState>LA</rptOwnerState>
            <rptOwnerZipCode>70130</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock no par value</value>
            </securityTitle>
            <transactionDate>
                <value>2009-10-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted stock units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Comm stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit represents a contingent right to receive one share of Whitney Holding Corporation common stock.</footnote>
        <footnote id="F2">The restricted stock units vest (become non-forfeitable) on the third anniversary of the grant date.  Vested restricted stock units convert to shares of common stock on the later of (i) within 30 days following the vesting date or (ii) the earliest permissible date such units may  convert to shares of common stock as a result of the issuer's receipt of financial assistance under the Department of the Treasury's Troubled Asset Relief Program.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Patricia K. Loupe, Sr. Assistant Corporate Secretary for Whitney Holding Corporation and attorney-in-fact</signatureName>
        <signatureDate>2009-10-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0303
4
2009-10-27
0000106926
WHITNEY HOLDING CORP
WTNY
0001453842
Cowell Elizabeth L
228 ST. CHARLES AVENUE
NEW ORLEANS
LA
70130
0
1
0
0
Executive Vice President
Common stock no par value
2009-10-27
4
P
0
2500
8.00
A
2500
D
Restricted stock units
Comm stock
7500
7500
D
Each restricted stock unit represents a contingent right to receive one share of Whitney Holding Corporation common stock.
The restricted stock units vest (become non-forfeitable) on the third anniversary of the grant date.  Vested restricted stock units convert to shares of common stock on the later of (i) within 30 days following the vesting date or (ii) the earliest permissible date such units may  convert to shares of common stock as a result of the issuer's receipt of financial assistance under the Department of the Treasury's Troubled Asset Relief Program.
Patricia K. Loupe, Sr. Assistant Corporate Secretary for Whitney Holding Corporation and attorney-in-fact
2009-10-28