-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 AZgXZ5d5jMpfAAy/ESVEZDd8dwdMMYC8Zg7NqkLxi3gkBbVNWOU0Nl2lFL+si3uk
 7JO4VQee9N+Pfb1yMmpzsA==

<SEC-DOCUMENT>0001005284-10-000003.txt : 20100105
<SEC-HEADER>0001005284-10-000003.hdr.sgml : 20100105
<ACCEPTANCE-DATETIME>20100105163648
ACCESSION NUMBER:		0001005284-10-000003
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20091231
FILED AS OF DATE:		20100105
DATE AS OF CHANGE:		20100105

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GEMMILL ELIZABETH H
		CENTRAL INDEX KEY:			0001200218
		STANDARD INDUSTRIAL CLASSIFICATION:	WATER SUPPLY [4941]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12031
		FILM NUMBER:		10507338

	BUSINESS ADDRESS:	
		STREET 1:		1025 LAUREL OAK RD
		CITY:			VOORHEES
		STATE:			NJ
		ZIP:			08043
		BUSINESS PHONE:		6093468200

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			UNIVERSAL DISPLAY CORP \PA\
		CENTRAL INDEX KEY:			0001005284
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRONIC COMPONENTS & ACCESSORIES [3670]
		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>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-12-31</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001200218</rptOwnerCik>
            <rptOwnerName>GEMMILL ELIZABETH H</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>2009-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1391</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>50715</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Steven V. Abramson (by power of attorney)</signatureName>
        <signatureDate>2010-01-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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