<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>1992-04-06</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000055362</issuerCik>
        <issuerName>KENTUCKY INVESTORS INC</issuerName>
        <issuerTradingSymbol>KINV</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001223521</rptOwnerCik>
            <rptOwnerName>INVESTORS HERITAGE LIFE INSURANCE CO</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Group (1)</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>
        <transactionDate>
            <value>2003-07-08</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>S</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>85</value>
            </transactionShares>
            <transactionValue>
                <value>26</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>D</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>174289</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
                <footnoteId id="F1"/>
            </directOrIndirectOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <footnotes>
        <footnote id="F1">(1) Explanation of the Group are Investors Heritage Life Insurance Company, Investors Underwriters, Inc., HLW Investment Corp., TAP &amp; CO., Harry Lee Waterfield II, RoseGayle Waterfield Hardy, Nancy Waterfield Walton, HLW Corporation, Harry Lee Waterfield II, RoseGayle Waterfield Hardy, Nancy Waterfield Walton TUA Fund 1,2, 3 and 4 and RoseGayle Waterfield, Nancy Waterfield Walton, Harry Lee Waterfield Trust dated 12-22-1976 and Kentucky Investors, Inc. Employee Retirement Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Jane S. Jackson, Asst Secretary on behalf of Investors Heritage Life Insurance Company</signatureName>
        <signatureDate>2003-07-09</signatureDate>
    </ownerSignature>

</ownershipDocument>

