|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |  Nicor                  Gas Company |   |
|------------------------------------------------------------------------------------------------------|--------|-----------------------------------|------------|-----------------------------------|--------|-----------------------------------------|--------|--------|---------|--------|--------------------------------------|------------------------------------------|--------|
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   | Form                  10-Q |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |  Exhibit                  12.01 |                                     |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |
| **Nicor                  Gas Company**                                                               |   |
| **Computation                  of Consolidated Ratio of Earnings to Fixed                  Charges** |   |
| (thousands)                                                                                          |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |
|                                                                                                 |   | **Three**                         |       | **Twelve**                        |   |                                    |   |   |    |   |                                 |                                     |   |   |   |
|                                                                                                 |   | **months                  ended** |       | **months                  ended** |   |                                    |   |   |    |   |                                 |                                     |   |   |   |
|                                                                                                 |   | **June                  30,**     |       | **June                  30,**     |   | Year                  Ended December 31 |   |
|                                                                                                 |   | **2006**                          |       | **2006**                          |   | 2005                                    |   | 2004   |    | 2003   |                                 | 2002                                     |   | 2001 |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
| Earnings                  available to cover fixed charges:                                          |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
| Net                  income                                                                          |   | **$**                             | **8,289**  |                              | **$**  | **55,896**                              |   | $      | 53,476  |   | $                                    | 62,106                                   |   | $ | 83,000 |   | $ | 109,139 |   | $ | 98,806 |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
| Add:                  Income tax expense                                                             |   |                              | **2,851**  |                              |   | **27,061**                              |   |   | 26,128  |   |                                 | 33,108                                   |   |   | 48,035 |   |   | 64,325 |   |   | 57,000 |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
|                        Fixed charges                                        |   |                              | **8,550**  |                              |   | **44,558**                              |   |   | 43,203  |   |                                 | 37,555                                   |   |   | 37,047 |   |   | 36,711 |   |   | 45,431 |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
|                        Allowance for funds                                  |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
|                          used during construction and other       |   |                              | **(123**   | **)**                             |   | **(1,190**                              | **)**  |   | (1,038  | )      |                                 | (363                                     | )      |   | (220 | ) |   | (395 | ) |   | (241 | ) |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
|                                                                                                 |   | **$**                             | **19,567** |                              | **$**  | **126,325**                             |   | $      | 121,769 |   | $                                    | 132,406                                  |   | $ | 167,862 |   | $ | 209,780 |   | $ | 200,996 |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
| Fixed                  charges:                                                                      |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
| Interest                  on debt                                                                    |   | **$**                             | **7,836**  |                              | **$**  | **38,108**                              |   | $      | 36,487  |   | $                                    | 35,606                                   |   | $ | 33,934 |   | $ | 33,037 |   | $ | 43,542 |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
| Other                  interest charges and                                                          |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
| amortization                  of debt discount,                                                      |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
| premium,                  and expense, net                                                           |   |                              | **714**    |                              |   | **6,450**                               |   |   | 6,716   |   |                                 | 1,949                                    |   |   | 3,113 |   |   | 3,674 |   |   | 1,889 |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
|                                                                                                 |   | **$**                             | **8,550**  |                              | **$**  | **44,558**                              |   | $      | 43,203  |   | $                                    | 37,555                                   |   | $ | 37,047 |   | $ | 36,711 |   | $ | 45,431 |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
|                                                                                                 |   |                              |       |                              |   |                                    |   |   |    |   |                                 |                                     |   |   |   |   |   |   |   |   |   |   |
| Ratio                  of earnings to fixed charges                                                  |   |                              | **2.29**   |                              |   | **2.84**                                |   |   | 2.82    |   |                                 | 3.53                                     |   |   | 4.53 |   |   | 5.71 |   |   | 4.42 |   |