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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2017-10-16</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001005201</issuerCik>
        <issuerName>DEPOMED INC</issuerName>
        <issuerTradingSymbol>DEPO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001386932</rptOwnerCik>
            <rptOwnerName>Vetticaden Santosh</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O DEPOMED INC.</rptOwnerStreet1>
            <rptOwnerStreet2>7999 GATEWAY BOULEVARD, SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>NEWARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94560</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP, Chief Medical Officer ***</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <remarks>* Santosh's title is Senior Vice President, Chief Medical and Scientific Officer.</remarks>

    <ownerSignature>
        <signatureName>/s/ Santosh J. Vetticaden</signatureName>
        <signatureDate>2017-10-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
