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Nicor Gas Company
Form 10-K
Exhibit 12.01

Nicor Gas Company
Computation of Consolidated Ratio of Earnings to Fixed Charges
(thousands)

|                                   |                                                                                     |                                              |         |                        |        |      |         |        |        |      |        |        |        |   |         |        |        |   |         |        |        |  
|---------------------------------- | ----------------------------------------------------------------------------------- | -------------------------------------------- | ------- | ---------------------- | ------ | ---- | ------- | ------ | ------ | ---- | ------ | ------ | ------ | - | ------- | ------ | ------ | - | ------- | ------ | ------ | -
|                                   |                                                                                     |                                              |         | Year ended December 31
|                                   |                                                                                     |                                              |         |                       
|                                   |                                                                                     |                                              |         | 2002                   |        | 2001 |         | 2000   |        | 1999 |        | 1998  
|                                   |                                                                                     |                                              |         |                        |        |      |         |        |        |      |        |       
|Earnings available to cover        |                                                                                     |                                              |         |                        |        |      |         |        |        |      |        |        |        |   |         |        |        |   |         |       
|                                   | fixed charges:                                                                      |                                              |         |                        |        |      |         |        |        |      |        |        |        |   |         |        |        |   |         |        |       
|                                   | Net income                                                                          |                                              | $       | 109,139                |        |      | $       | 98,806 |        |      | $      | 12,584 |        |   | $       | 96,010 |        |   | $       | 94,119 |       
|                                   | Add: Income taxes                                                                   |                                              |         | 64,325                 |        |      |         | 57,000 |        |      |        | 520    |        |   |         | 55,809 |        |   |         | 55,299 |       
|                                   |                                                                                     | Fixed charges                                |         |                        | 36,711 |      |         |        | 45,431 |      |        |        | 44,863 |   |         |        | 38,917 |   |         |        | 44,870 |  
|                                   |                                                                                     | Allowance for funds used
during construction |         |                        | (395   | )    |         |        | (241   | )    |        |        | (363   | ) |         |        | (118   | ) |         |        | (269   | )
|                                   |                                                                                     |                                              |         |                        |        |      |         |        |        |      |        |        |        |   |         |        |        |   |         |       
|                                   |                                                                                     | $                                            | 209,780 |                        |        | $    | 200,996 |        |        | $    | 57,604 |        |        | $ | 190,618 |        |        | $ | 194,019 |       
|                                   |                                                                                     |                                              |         |                        |        |      |         |        |        |      |        |        |        |   |         |        |        |   |         |       
|Fixed charges:                     |                                                                                     |                                              |         |                        |        |      |         |        |        |      |        |        |        |   |         |        |        |   |         |       
|                                   | Interest on debt                                                                    |                                              | $       | 33,037                 |        |      | $       | 43,542 |        |      | $      | 42,365 |        |   | $       | 39,245 |        |   | $       | 42,624 |       
|                                   | Other interest charges and
amortization of debt discount,
premium, and expense, net |                                              |         | 3,674                  |        |      |         | 1,889  |        |      |        | 2,498  |        |   |         | (328   | )      |   |         | 2,246  |       
|                                   |                                                                                     |                                              |         |                        |        |      |         |        |        |      |        |        |        |   |         |        |        |   |         |       
|                                   |                                                                                     | $                                            | 36,711  |                        |        | $    | 45,431  |        |        | $    | 44,863 |        |        | $ | 38,917  |        |        | $ | 44,870  |       
|                                   |                                                                                     |                                              |         |                        |        |      |         |        |        |      |        |        |        |   |         |        |        |   |         |       
|Ratio of earnings to fixed charges |                                                                                     |                                              | 5.71    |                        |        |      | 4.42    |        |        |      | 1.28   |        |        |   | 4.90    |        |        |   | 4.32    |       
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