-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 BlLRC7kyNBP158gdASACsw==

<SEC-DOCUMENT>0001065407-10-000251.txt : 20100511
<SEC-HEADER>0001065407-10-000251.hdr.sgml : 20100511
<ACCEPTANCE-DATETIME>20100511110942
ACCESSION NUMBER:		0001065407-10-000251
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100507
FILED AS OF DATE:		20100511
DATE AS OF CHANGE:		20100511

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MULCAHY FRANCIS V
		CENTRAL INDEX KEY:			0001339204

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51214
		FILM NUMBER:		10819552

	MAIL ADDRESS:	
		STREET 1:		PRUDENTIAL BANCORP INC OF PENNSYLVANIA
		STREET 2:		1834 OREGON AVENUE
		CITY:			PHILADELPHIA
		STATE:			PA
		ZIP:			19145

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PRUDENTIAL BANCORP INC OF PENNSYLVANIA
		CENTRAL INDEX KEY:			0001302324
		STANDARD INDUSTRIAL CLASSIFICATION:	SAVINGS INSTITUTIONS, NOT FEDERALLY CHARTERED [6036]
		IRS NUMBER:				680593604
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		1834 OREGON AVENUE
		CITY:			PHILADELPHIA
		STATE:			PA
		ZIP:			19145
		BUSINESS PHONE:		(215) 755-1500

	MAIL ADDRESS:	
		STREET 1:		1834 OREGON AVENUE
		CITY:			PHILADELPHIA
		STATE:			PA
		ZIP:			19145
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-05-07</periodOfReport>

    <issuer>
        <issuerCik>0001302324</issuerCik>
        <issuerName>PRUDENTIAL BANCORP INC OF PENNSYLVANIA</issuerName>
        <issuerTradingSymbol>PBIP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001339204</rptOwnerCik>
            <rptOwnerName>MULCAHY FRANCIS V</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PRUDENTIAL SAVINGS BANK</rptOwnerStreet1>
            <rptOwnerStreet2>1834 OREGON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>PHILADELPHIA</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19145</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-05-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.44</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14307</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>11.17</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-01-05</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>28268</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>28268</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Includes 9,046 shares granted pursuant to the 2008 Recognition and Retention Plan (&quot;RRP&quot;)  and held in the RRP Trust that are vesting 20% per year commencing on January 5, 2010.</footnote>
        <footnote id="F2">The options are vesting in five equal annual installments beginning on January 5, 2010.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/Joseph R. Corrato, Attorney-in-Fact for Francis V. Mulcahy</signatureName>
        <signatureDate>2010-05-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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