UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 4, 2012

THE MOSAIC COMPANY

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (800) 918-8270

Not applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Item 5.07. Submission of Matters to a Vote of Security Holders.

On October 4, 2012, at the Annual Meeting of Stockholders (the “Annual Meeting”) of The Mosaic Company, a Delaware corporation (“Mosaic”), the Mosaic stockholders elected four directors (Phyllis E. Cochran, Gregory L. Ebel, Robert L. Lumpkins and William T. Monahan), each for a term of three years expiring in 2015 or until their respective successors have been duly elected and qualified; (ii) ratified the election of Harold H. MacKay to fill a vacancy in the class of directors whose term expires in 2013; (iii) ratified the appointment of KPMG LLP as the independent registered public accounting firm to audit Mosaic’s financial statements for the fiscal year ending May 31, 2013; and (iv) approved, on an advisory basis, the compensation of Mosaic’s Named Executive Officers, as described in the Compensation Discussion and Analysis section, the compensation tables and the related narrative disclosures set forth in Mosaic’s proxy statement for the Annual Meeting (the “Say-on-Pay Advisory Proposal”).

The votes cast with respect to each director elected for a term of three years expiring in 2015 are summarized as follows:

The votes cast with respect to ratification of the election of Mr. MacKay to fill a vacancy in the class of directors whose term expires in 2013 are summarized as follows:

The votes cast with respect to ratification of the appointment of KPMG LLP as Mosaic’s independent registered public accounting firm to audit Mosaic’s consolidated financial statements for the fiscal year ending May 31, 2012 are summarized as follows:

The votes cast with respect to approval, on an advisory basis, of the Say-on-Pay Advisory Proposal are summarized as follows:

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.