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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-12-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000067625</issuerCik>
        <issuerName>MONMOUTH REAL ESTATE INVESTMENT CORP</issuerName>
        <issuerTradingSymbol>mnr</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000752642</rptOwnerCik>
            <rptOwnerName>UMH PROPERTIES, INC.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3499 ROUTE 9 N, SUITE 3-C</rptOwnerStreet1>
            <rptOwnerStreet2>JUNIPER BUSINESS PLAZA</rptOwnerStreet2>
            <rptOwnerCity>FREEHOLD</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07728</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Affiliate</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Monmouth Real Estate Investment Corporation</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1627387.935</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Includes 16,461.1650 shares acquired through dividend reinvestment.

Note that the total number of securities beneficially owned by UMH is 1,627,387.935 shares.  This reflects a decrease of 436,681 shares as previously recorded on Form 4 dated 9/15/2010.  On December 13, 2010, Monmouth Real Estate repurchased the $5,000,000 MCC Subordinated Debentures, due 2015, held by UMH.  That bond reflected 436,681 common shares of Monmouth Real Estate which were issuable upon conversion of the 2005 Debentures, and were previously included in UMH's holdings in Monmouth Real Estate.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Susan M. Jordan</signatureName>
        <signatureDate>2010-12-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
