-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001181431-05-044209.txt : 20050803
<SEC-HEADER>0001181431-05-044209.hdr.sgml : 20050803
<ACCEPTANCE-DATETIME>20050803172201
ACCESSION NUMBER:		0001181431-05-044209
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050801
FILED AS OF DATE:		20050803
DATE AS OF CHANGE:		20050803

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MOSAIC CO
		CENTRAL INDEX KEY:			0001285785
		STANDARD INDUSTRIAL CLASSIFICATION:	AGRICULTURE CHEMICALS [2870]
		IRS NUMBER:				200891589
		FISCAL YEAR END:			0531

	BUSINESS ADDRESS:	
		STREET 1:		15407 MCGINTY RD
		CITY:			MINNETONKA
		STATE:			MN
		ZIP:			55391
		BUSINESS PHONE:		9527426395

	MAIL ADDRESS:	
		STREET 1:		15407 MCGINTY RD
		CITY:			MINNETONKA
		STATE:			MN
		ZIP:			53391

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	GLOBAL NUTRITION SOLUTIONS INC
		DATE OF NAME CHANGE:	20040401

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WESSLING DAVID W
		CENTRAL INDEX KEY:			0001320984

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32327
		FILM NUMBER:		05996601

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		(952) 984-0250

	MAIL ADDRESS:	
		STREET 1:		12800 WHITEWATER DRIVE
		STREET 2:		SUITE 200
		CITY:			MINNETONKA
		STATE:			MN
		ZIP:			55343

	FORMER NAME:	
		FORMER CONFORMED NAME:	WESSLING DAVID L
		DATE OF NAME CHANGE:	20050317
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>rrd87655.xml
<DESCRIPTION>08/01/05 FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-08-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001285785</issuerCik>
        <issuerName>MOSAIC CO</issuerName>
        <issuerTradingSymbol>MOS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001320984</rptOwnerCik>
            <rptOwnerName>WESSLING DAVID W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3033 CAMPUS DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE E490</rptOwnerStreet2>
            <rptOwnerCity>PLYMOUTH</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55441</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Grant of Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-08-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>12369</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2008-08-01</value>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>12369</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>12369</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Grant of Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>17.29</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-08-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>37106</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2006-08-01</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-08-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>37106</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>37106</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Not applicable.</footnote>
        <footnote id="F2">Vests 33.33% on August 1, 2006, August 1, 2007 and August 1, 2008.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Richard L. Mack, Attorney in fact for David W. Wessling</signatureName>
        <signatureDate>2005-08-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----