<SEC-DOCUMENT>0001214659-15-000417.txt : 20150120
<SEC-HEADER>0001214659-15-000417.hdr.sgml : 20150119
<ACCEPTANCE-DATETIME>20150120135244
ACCESSION NUMBER:		0001214659-15-000417
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20150115
FILED AS OF DATE:		20150120
DATE AS OF CHANGE:		20150120

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ONE LIBERTY PROPERTIES INC
		CENTRAL INDEX KEY:			0000712770
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				133147497
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		60 CUTTER MILL RD
		STREET 2:		SUITE 303
		CITY:			GREAT NECK
		STATE:			NY
		ZIP:			11021-3190
		BUSINESS PHONE:		5164663100

	MAIL ADDRESS:	
		STREET 1:		60 CUTTER MILL ROAD
		STREET 2:		SUITE 303
		CITY:			GREAT NECK
		STATE:			NY
		ZIP:			11021-3190

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ONE LIBERTY FIRESTONE PROPERTIES INC
		DATE OF NAME CHANGE:	19851112

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CALLAN PATRICK JR
		CENTRAL INDEX KEY:			0001187921

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09279
		FILM NUMBER:		15535323
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>marketforms-28246.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-01-15</periodOfReport>

    <issuer>
        <issuerCik>0000712770</issuerCik>
        <issuerName>ONE LIBERTY PROPERTIES INC</issuerName>
        <issuerTradingSymbol>OLP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001187921</rptOwnerCik>
            <rptOwnerName>CALLAN PATRICK JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>60 CUTTER MILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 303</rptOwnerStreet2>
            <rptOwnerCity>GREAT NECK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>11021</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>2015-01-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>18000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>113563</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">These shares were issued as restricted stock effective January 15, 2015 under the issuer's 2012 Incentive Plan.  The shares vest January 14, 2020.  The award is exempt from Section 16(b) under Rule 16b-3(d)(1).</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Patrick Callan</signatureName>
        <signatureDate>2015-01-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
