FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * DUNN E PAUL JR   2. Issuer Name and Ticker or Trading Symbol MOSAIC CO [MOS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Vice President and Treasurer (Last) (First) (Middle) 12800 WHITEWATER DRIVE, SUITE 200 3. Date of Earliest Transaction (Month/Day/Year) 10/22/2004 (Street) MINNETONKA, MN 55343 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 10/22/2004   A   16,615 A (1) 16,615 D

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Stock Option (right to buy)

$ 34.875

10/22/2004

A

12,500

10/22/2004

05/12/2008

Common Stock

12,500

$ 34.875 (2)

12,500

D

Stock Option (right to buy)

$ 30.656

10/22/2004

A

3,300

10/22/2004

06/18/2008

Common Stock

3,300

$ 30.656 (2)

3,300

D

Stock Option (right to buy)

$ 22.6562

10/22/2004

A

16,600

10/22/2004

04/27/2009

Common Stock

16,600

$ 22.6562 (2)

16,600

D

Stock Option (right to buy)

$ 15.0312

10/22/2004

A

27,000

10/22/2004

02/22/2010

Common Stock

27,000

$ 15.0312 (2)

27,000

D

Stock Option (right to buy)

$ 15.0625

10/22/2004

A

16,700

10/22/2004

03/30/2010

Common Stock

16,700

$ 15.0625 (2)

16,700

D

Stock Option (right to buy)

$ 13.55

10/22/2004

A

45,000

10/22/2004

02/28/2011

Common Stock

45,000

$ 13.55 (2)

45,000

D

Stock Option (right to buy)

$ 10.71

10/22/2004

A

50,000

10/22/2004

11/05/2011

Common Stock

50,000

$ 10.71 (2)

50,000

D

Stock Option (right to buy)

$ 10.76

10/22/2004

A

35,000

10/22/2004

01/02/2013

Common Stock

35,000

$ 10.76 (2)

35,000

D

Stock Option (right to buy)

$ 10.19

10/22/2004

A

35,000

10/22/2004

01/02/2014

Common Stock

35,000

$ 10.19 (2)

35,000

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
DUNN E PAUL JR 12800 WHITEWATER DRIVE SUITE 200 MINNETONKA, MN 55343			Vice President and Treasurer

Signatures

s/ Richard L. Mack		10/26/2004
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Received in exchange for 20,788 shares of IMC Global Inc. common stock with merger of IMC Global (the "Merger"). On the effective date of the Merger, the closing price of IMC Global's common stock was $15.00 per share.
(2)	Received in the Merger in exchange for a stock option to acquire the same number of IMC Global common stock at the same price per share.

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