<SEC-DOCUMENT>0001214659-17-000726.txt : 20170206
<SEC-HEADER>0001214659-17-000726.hdr.sgml : 20170206
<ACCEPTANCE-DATETIME>20170206150550
ACCESSION NUMBER:		0001214659-17-000726
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170206
FILED AS OF DATE:		20170206
DATE AS OF CHANGE:		20170206

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FAIR ISAAC CORP
		CENTRAL INDEX KEY:			0000814547
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-BUSINESS SERVICES, NEC [7389]
		IRS NUMBER:				941499887
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		181 METRO DRIVE
		STREET 2:		SUITE 700
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95110
		BUSINESS PHONE:		(408) 535-1500

	MAIL ADDRESS:	
		STREET 1:		181 METRO DRIVE
		STREET 2:		SUITE 700
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95110

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FAIR ISAAC & COMPANY INC
		DATE OF NAME CHANGE:	19920703

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LANSING WILLIAM J
		CENTRAL INDEX KEY:			0001074500
		STANDARD INDUSTRIAL CLASSIFICATION:	RETAIL-CATALOG & MAIL-ORDER HOUSES [5961]
		STATE OF INCORPORATION:			MN
		FISCAL YEAR END:			1228

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-11689
		FILM NUMBER:		17575353

	MAIL ADDRESS:	
		STREET 1:		NET PERCEPTIONS, INC
		STREET 2:		7700 FRANCE AVENUE SOUTH
		CITY:			EDINA
		STATE:			MN
		ZIP:			55435
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>marketforms-37763.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-02-06</periodOfReport>

    <issuer>
        <issuerCik>0000814547</issuerCik>
        <issuerName>FAIR ISAAC CORP</issuerName>
        <issuerTradingSymbol>FICO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001074500</rptOwnerCik>
            <rptOwnerName>LANSING WILLIAM J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>181 METRO DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN JOSE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95110</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-02-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>123.62</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>188321</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Shares sold pursuant to reporting person's 10b5-1 plan.</footnote>
        <footnote id="F2">This transaction was executed in multiple trades at prices ranging from $123.261 to $123.82. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/Nancy E. Fraser, Attorney-in-fact</signatureName>
        <signatureDate>2017-02-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
