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

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2000-01-01</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000275694</issuerCik>
        <issuerName>MASSMUTUAL CORPORATE INVESTORS</issuerName>
        <issuerTradingSymbol>MCI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000009015</rptOwnerCik>
            <rptOwnerName>BABSON CAPITAL MANAGEMENT LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1500 MAIN STREET</rptOwnerStreet1>
            <rptOwnerStreet2>PO BOX 15189</rptOwnerStreet2>
            <rptOwnerCity>SPRINGFIELD</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01115-5189</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Inv. Adviser (see note below)</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <footnotes></footnotes>

    <remarks>Babson Capital Management LLC (formerly David L. Babson and Company Inc) is a wholly-owned indirect subsidiary of Massachusetts Mutual Life Insurance Company.</remarks>

    <ownerSignature>
        <signatureName>By: Rodney J. Dillman</signatureName>
        <signatureDate>2007-09-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
