-----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,
 RCpfARqhb21wnBUMAxW8Wmgefk09ApM3icbjxfjGFFoCofqC28HEpD7MEXzzx/Em
 q5om1d7i3jeanbNv5GcLvQ==

<SEC-DOCUMENT>0001394784-09-000003.txt : 20090616
<SEC-HEADER>0001394784-09-000003.hdr.sgml : 20090616
<ACCEPTANCE-DATETIME>20090616142145
ACCESSION NUMBER:		0001394784-09-000003
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090615
FILED AS OF DATE:		20090616
DATE AS OF CHANGE:		20090616

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Treska Edward Joseph
		CENTRAL INDEX KEY:			0001394784

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-26068
		FILM NUMBER:		09893846

	MAIL ADDRESS:	
		STREET 1:		500 NEWPORT CENTER DRIVE
		STREET 2:		7TH FLOOR
		CITY:			NEWPORT BEACH
		STATE:			CA
		ZIP:			92660

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ACACIA RESEARCH CORP
		CENTRAL INDEX KEY:			0000934549
		STANDARD INDUSTRIAL CLASSIFICATION:	PATENT OWNERS & LESSORS [6794]
		IRS NUMBER:				954405754
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		500 NEWPORT CENTER DRIVE
		STREET 2:		7TH FLOOR
		CITY:			NEWPORT BEACH
		STATE:			CA
		ZIP:			92660
		BUSINESS PHONE:		9494808300

	MAIL ADDRESS:	
		STREET 1:		500 NEWPORT CENTER DRIVE
		STREET 2:		#
		CITY:			NEWPORT BEACH
		STATE:			CA
		ZIP:			92660
</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>2009-06-15</periodOfReport>

    <issuer>
        <issuerCik>0000934549</issuerCik>
        <issuerName>ACACIA RESEARCH CORP</issuerName>
        <issuerTradingSymbol>ACTG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001394784</rptOwnerCik>
            <rptOwnerName>Treska Edward Joseph</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>500 NEWPORT CENTER DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>7TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEWPORT BEACH</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92660</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>V.P., Secretary</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-06-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5363</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.63</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>105007</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Edward J. Treska</signatureName>
        <signatureDate>2009-06-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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