Exhibit 11.1

WESTERN
GAS RESOURCES, INC.
COMPUTATION OF PER SHARE EARNINGS
DECEMBER 31, 2002

|                                                                                                                      |                                                                    | Weighted Average Shares Of Common Stock Outstanding |  | Net
Income |            | Earnings Per Share Of Common Stock
|--------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------ | --------------------------------------------------- |  | ---------- | ---------- | ----------------------------------
|Net income                                                                                                            |                                                                    |                                                     |  | $          | 50,589,000 |                                   
|Weighted average shares of common stock outstanding                                                                   |                                                                    | 32,952,543                                          |  |            |            |                                   
|Less preferred stock dividends:                                                                                       |                                                                    |                                                     |  |            |            |                                   
|                                                                                                                      | $2.28 cumulative preferred stock                                   |                                                     |  |            |            | (1,265,053                        
|                                                                                                                      | Special dividend on redemption of $2.28 cumulative preferred stock |                                                     |  |            |            | (688,000                          
|                                                                                                                      | $2.625 cumulative convertible preferred stock                      |                                                     |  |            |            | (7,245,000                        
|                                                                                                                      |                                                                    |                                                     |  |            |            |                                   
|                                                                                                                      |                                                                    | 32,952,543                                          |  | $          | 41,390,947 |                                   
|                                                                                                                      |                                                                    |                                                     |  |            |            |                                   
|Basic earnings per share of common stock                                                                              |                                                                    |                                                     |  |            |            |                                   
|                                                                                                                      |                                                                    |                                                     |  |            |            |                                   
|Assume exercise of common stock equivalents (Anti-dilutive common stock equivalents are not used in this calculation) |                                                                    | 655,017                                             |  |            |            |                                   
|                                                                                                                      |                                                                    | 33,607,560                                          |  | $          | 41,390,947 |                                   
|                                                                                                                      |                                                                    |                                                     |  |            |            |                                   
|Fully diluted earnings per share of common stock                                                                      |                                                                    |                                                     |  |            |            |                                   
|                                                                                                                      |                                                                    |                                                     |  |            |            |                                   



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