-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 V4n+TVkzOTJN+OdPknzNOiTIG5WrXQ7jJHD6Owur4eayghZMNOLOtA3sLuZEiAv4
 YoCGKKrChFEUC6cHQokxHg==

<SEC-DOCUMENT>0001005284-06-000015.txt : 20060104
<SEC-HEADER>0001005284-06-000015.hdr.sgml : 20060104
<ACCEPTANCE-DATETIME>20060104161804
ACCESSION NUMBER:		0001005284-06-000015
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20051230
FILED AS OF DATE:		20060104
DATE AS OF CHANGE:		20060104

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LACERTE LAWRENCE
		CENTRAL INDEX KEY:			0001101463

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12031
		FILM NUMBER:		06507947

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		8584045500

	MAIL ADDRESS:	
		STREET 1:		C/O TERAGLOBAL COMMUNICATIONS CORP
		STREET 2:		9171 TOWNE CENTRE DRIVE SUITE 600
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92122

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			UNIVERSAL DISPLAY CORP \PA\
		CENTRAL INDEX KEY:			0001005284
		STANDARD INDUSTRIAL CLASSIFICATION:	COMPUTER TERMINALS [3575]
		IRS NUMBER:				232372688
		STATE OF INCORPORATION:			PA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		375 PHILLIPS BOULEVARD
		CITY:			EWING
		STATE:			NJ
		ZIP:			08618
		BUSINESS PHONE:		6096710980

	MAIL ADDRESS:	
		STREET 1:		375 PHILLIPS BOULEVARD
		STREET 2:		375 PHILLIPS BOULEVARD
		CITY:			EWING
		STATE:			NJ
		ZIP:			08618
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-12-30</periodOfReport>

    <issuer>
        <issuerCik>0001005284</issuerCik>
        <issuerName>UNIVERSAL DISPLAY CORP \PA\</issuerName>
        <issuerTradingSymbol>PANL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001101463</rptOwnerCik>
            <rptOwnerName>LACERTE LAWRENCE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>375 PHILLIPS BLVD.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>EWING</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>08618</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>2006-01-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>7500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>907500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>10.51</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-12-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>25000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2005-12-30</value>
            </exerciseDate>
            <expirationDate>
                <value>2015-12-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>25000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>25000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Sidney D. Rosenblatt (by power of attorney)</signatureName>
        <signatureDate>2006-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----