-----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,
 ReXPZpju8DcZ5YyJl15L08blsRBZfj62ZFk+3Xi0lWMt4PpsTZ1gRjPtodlDS6O6
 v5m3KxS5oRu/1bKXuSE/yA==

<SEC-DOCUMENT>0001126328-08-000402.txt : 20081209
<SEC-HEADER>0001126328-08-000402.hdr.sgml : 20081209
<ACCEPTANCE-DATETIME>20081209190134
ACCESSION NUMBER:		0001126328-08-000402
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20081205
FILED AS OF DATE:		20081209
DATE AS OF CHANGE:		20081209

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LAMALE ELLEN Z
		CENTRAL INDEX KEY:			0001166869

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-16725
		FILM NUMBER:		081239516

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		5152359417

	MAIL ADDRESS:	
		STREET 1:		711 HIGH STREET
		CITY:			DES MOINES
		STATE:			IA
		ZIP:			50392-0300

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PRINCIPAL FINANCIAL GROUP INC
		CENTRAL INDEX KEY:			0001126328
		STANDARD INDUSTRIAL CLASSIFICATION:	ACCIDENT & HEALTH INSURANCE [6321]
		IRS NUMBER:				421520346
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		711 HIGH STREET
		CITY:			DES MOINES
		STATE:			IA
		ZIP:			50392-0300
		BUSINESS PHONE:		5152475111

	MAIL ADDRESS:	
		STREET 1:		711 HIGH STREET
		CITY:			DES MOINES
		STATE:			IA
		ZIP:			50392-0300
</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>2008-12-05</periodOfReport>

    <issuer>
        <issuerCik>0001126328</issuerCik>
        <issuerName>PRINCIPAL FINANCIAL GROUP INC</issuerName>
        <issuerTradingSymbol>PFG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001166869</rptOwnerCik>
            <rptOwnerName>LAMALE ELLEN Z</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>711 HIGH STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DES MOINES</rptOwnerCity>
            <rptOwnerState>IA</rptOwnerState>
            <rptOwnerZipCode>50392</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr. VP &amp; Chief Actuary</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-12-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>28.1</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.20</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>28.1</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1226.4</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Security converts to common stock on a one-for-one basis.</footnote>
        <footnote id="F2">The reported phantom stock units were acquired pursuant to the Principal Select Savings Excess Plan and may be transferred at any time into another investment alternative under the Plan.  Interests under the Plan will be settled upon the reporting person's retirement or other termination of service.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Joyce E. Hoffman, by Power of Attorney</signatureName>
        <signatureDate>2008-12-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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