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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-06-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000845877</issuerCik>
        <issuerName>FEDERAL AGRICULTURAL MORTGAGE CORP</issuerName>
        <issuerTradingSymbol>AGM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000109380</rptOwnerCik>
            <rptOwnerName>ZIONS BANCORPORATION /UT/</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE SOUTH MAIN STREET, SUITE 1134</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SALT LAKE CITY</rptOwnerCity>
            <rptOwnerState>UT</rptOwnerState>
            <rptOwnerZipCode>84111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class C Non-Voting / Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-06-13</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5000.</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>25.7504</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>960000.</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class C Non-Voting / Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-06-14</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5000.</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>25.7424</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>955000.</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <ownerSignature>
        <signatureName>By: /s/ W. David Hemingway, Executive Vice President</signatureName>
        <signatureDate>2006-06-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2006-06-13
0
0000845877
FEDERAL AGRICULTURAL MORTGAGE CORP
AGM
0000109380
ZIONS BANCORPORATION /UT/
ONE SOUTH MAIN STREET, SUITE 1134
SALT LAKE CITY
UT
84111
0
0
1
0
Class C Non-Voting / Common Stock
2006-06-13
4
S
0
5000.
25.7504
D
960000.
D
Class C Non-Voting / Common Stock
2006-06-14
4
S
0
5000.
25.7424
D
955000.
D
By: /s/ W. David Hemingway, Executive Vice President
2006-06-14