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

December 3, 2013

(Date of earliest event reported)

Potash Corporation of Saskatchewan Inc.

(Exact name of registrant as specified in its charter)

Suite 500, 122 - 1^st Avenue South

Saskatoon, Saskatchewan, Canada S7K 7G3

(Address of principal executive offices, including zip code)

306 / 933-8500

(Registrant’s telephone number, including area code)

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.):

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

On December 3, 2013, Potash Corporation of Saskatchewan Inc. (the “Company”) issued a news release announcing operating changes and a related reduction in its workforce in Canada, the United States and Trinidad by approximately 18 percent from current levels. One-time costs associated with these changes are expected to approximate $70 million for severance charges. The Company is currently reviewing the carrying value of its affected assets and a write-down, if required, will be incorporated into its fourth quarter 2013 results. These operating and workforce changes are described in greater detail in the Company’s news release, a copy of which is attached hereto as Exhibit 99.1 and incorporated herein by reference.

This Current Report on Form 8-K contains forward-looking statements or forward-looking information (forward-looking statements). These statements can be identified by expressions of belief, expectation or intention, as well as those statements that are not historical fact. These statements are based on certain factors and assumptions including with respect to: foreign exchange rates, expected growth, results of operations, performance, business prospects and opportunities and effective tax rates. While the Company considers these factors and assumptions to be reasonable based on information currently available, they may prove to be incorrect. Forward-looking statements are subject to risks and uncertainties that are difficult to predict. The results or events set forth in forward-looking statements may differ materially from actual results or events. Several factors could cause actual results or events to differ materially from those expressed in the forward-looking statements, including, but not limited to the following: variations from our assumptions with respect to foreign exchange rates, expected growth, results of operations, performance, business prospects and opportunities, and effective tax rates; fluctuations in supply and demand in the fertilizer, sulfur, transportation and petrochemical markets; costs and availability of transportation and distribution for our raw materials and products, including railcars and ocean freight; changes in competitive pressures, including pricing pressures; adverse or uncertain economic conditions and changes in credit and financial markets; the results of sales contract negotiations within major markets; economic and political uncertainty around the world; timing and impact of capital expenditures; risks associated with natural gas and other hedging activities; changes in capital markets; unexpected or adverse weather conditions; changes in currency and exchange rates; unexpected geological or environmental conditions, including water inflows; imprecision in reserve estimates; adverse developments in new and pending legal proceedings or government investigations; acquisitions we may undertake; strikes or other forms of work stoppage or slowdowns; rates of return on and the risks associated with our investments; changes in, and the effects of, government policies and regulations; security risks related to our information technology systems; and earnings and the decisions of taxing authorities, which could affect our effective tax rates. Additional risks and uncertainties can be found in our Form 10-K for the fiscal year ended December 31, 2012 under the captions “Forward-Looking Statements” and “Item 1A – Risk Factors” and in our other filings with the U.S. Securities and Exchange Commission and the Canadian provincial securities commissions. Forward-looking statements are given only as at the date of this Current Report on Form 8-K and the Company disclaims any obligation to update or revise the forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

SIGNATURE

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.

Dated: December 4, 2013

Index to Exhibits