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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,
 BClk5zjDtusNMhn2pEhtPeo6mmKn33NVZny11oedfWiiyMl7I7YbSYXt22K8iHjJ
 3vEnG92FCNJDjUP0GOIKsg==

<SEC-DOCUMENT>0000916480-09-000091.txt : 20090420
<SEC-HEADER>0000916480-09-000091.hdr.sgml : 20090420
<ACCEPTANCE-DATETIME>20090420124058
ACCESSION NUMBER:		0000916480-09-000091
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090416
FILED AS OF DATE:		20090420
DATE AS OF CHANGE:		20090420

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FREELS GARY W
		CENTRAL INDEX KEY:			0001194330

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13923
		FILM NUMBER:		09758564

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			WAUSAU PAPER CORP.
		CENTRAL INDEX KEY:			0000105076
		STANDARD INDUSTRIAL CLASSIFICATION:	PAPER MILLS [2621]
		IRS NUMBER:				390690900
		STATE OF INCORPORATION:			WI
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		100 PAPER PLACE
		STREET 2:		ATTN:  SHERRI L. LEMMER
		CITY:			MOSINEE
		STATE:			WI
		ZIP:			54455
		BUSINESS PHONE:		7156934470

	MAIL ADDRESS:	
		STREET 1:		100 PAPER PLACE
		STREET 2:		ATTN:  SHERRI L. LEMMER
		CITY:			MOSINEE
		STATE:			WI
		ZIP:			54455

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	WAUSAU MOSINEE PAPER CORP
		DATE OF NAME CHANGE:	20030212

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	WAUSAU MOSINEE PAPER MILLS CORP
		DATE OF NAME CHANGE:	19980114
</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>2009-04-16</periodOfReport>

    <issuer>
        <issuerCik>0000105076</issuerCik>
        <issuerName>WAUSAU PAPER CORP.</issuerName>
        <issuerTradingSymbol>WPP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001194330</rptOwnerCik>
            <rptOwnerName>FREELS GARY W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>500 FIRST STREET</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 2137</rptOwnerStreet2>
            <rptOwnerCity>WAUSAU</rptOwnerCity>
            <rptOwnerState>WI</rptOwnerState>
            <rptOwnerZipCode>54402-2137</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.96</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-04-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2009-04-16</value>
            </exerciseDate>
            <expirationDate>
                <value>2019-04-16</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Sherri L. Lemmer, Attorney-in-Fact</signatureName>
        <signatureDate>2009-04-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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