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Exhibit 11

POTASH CORPORATION OF SASKATCHEWAN INC.
COMPUTATION OF PER SHARE EARNINGS
FOR THE THREE MONTHS ENDED MARCH 31

|  |  |                                                                           |  |      |            |      |  |   |            | 
|- |  | ------------------------------------------------------------------------- |  | ---- | ---------- | ---- |  | - | ---------- | 
|  |  |                                                                           |  | 2003 |            | 2002
|  |  |                                                                           |  |      |            |     
|A |  | Net income as reported, Canadian GAAP ($ millions)                        |  | $    | 3.2        |      |  | $ | 12.8       | 
|  |  |                                                                           |  |      |            |      |  |   |            | 
|B |  | Items adjusting net income ($ millions)                                   |  | $    | 1.6        |      |  | $ | 1.3        | 
|  |  |                                                                           |  |      |            |      |  |   |            | 
|C |  | Net income, US GAAP ($ millions)                                          |  | $    | 4.8        |      |  | $ | 14.1       | 
|  |  |                                                                           |  |      |            |      |  |   |            | 
|D |  | Weighted average number of shares outstanding                             |  |      | 52,089,000 |      |  |   | 51,960,000 | 
|  |  |                                                                           |  |      |            |      |  |   |            | 
|E |  | Net additional shares issuable for diluted
earnings per share calculation |  |      | 223,000    |      |  |   | 258,000    | 
|  |  |                                                                           |  |      |            |      |  |   |            | 
|  |  | CANADIAN GAAP                                                             |  |      |            |      |  |   |            | 
|  |  |                                                                           |  |      |            |      |  |   |            | 
|  |  | Basic earnings per share (A/D)                                            |  | $    | 0.06       |      |  | $ | 0.25       | 
|  |  |                                                                           |  |      |            |      |  |   |            | 
|  |  | Diluted earnings per share (A/(D+E))                                      |  | $    | 0.06       |      |  | $ | 0.24       | 
|  |  |                                                                           |  |      |            |      |  |   |            | 
|  |  | UNITED STATES GAAP                                                        |  |      |            |      |  |   |            | 
|  |  |                                                                           |  |      |            |      |  |   |            | 
|  |  | Basic earnings per share (C/D)                                            |  | $    | 0.09       |      |  | $ | 0.27       | 
|  |  |                                                                           |  |      |            |      |  |   |            | 
|  |  | Diluted earnings per share (C/(D+E))                                      |  | $    | 0.09       |      |  | $ | 0.27       |