|                                                                                               |   |     |   |                                   |   |        |   |   |             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 |   |        |   |
|                                                                                               |   |     |   |  **2006**                              |   | 2005        |   | 2004   |                                                                                                   | 2003 |   | 2002 |   |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
| Earnings                available to cover fixed charges:                                          |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
| Net                income                                                                          |   |     |   |                                        | **$**  | **58,656**  |   | $      | 53,476                                                                                                 |   | $ | 62,106 |   | $ | 83,000 |   | $ | 109,139 |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
| Add:                 Income tax expense                                                       |   |     |   |                                        |   | **27,814**  |   |   | 26,128                                                                                                 |   |   | 33,108 |   |   | 48,035 |   |   | 64,325 |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
|                       Fixed charges                                  |   |     |   |                                        |   | **45,041**  |   |   | 43,203                                                                                                 |   |   | 37,555 |   |   | 37,047 |   |   | 36,711 |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
|                       Allowance for funds                            |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
|                         used during construction and other |   |     |   |                                        |   | **(614**    | **)**  |   | (1,038                                                                                                 | ) |   | (363 | ) |   | (220 | ) |   | (395 | ) |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                               |   |     |   |                                        | **$**  | **130,897** |   | $      | 121,769                                                                                                |   | $ | 132,406 |   | $ | 167,862 |   | $ | 209,780 |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
| Fixed                charges:                                                                      |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
| Interest                on debt                                                                    |   |     |   |                                        | **$**  | **37,665**  |   | $      | 36,487                                                                                                 |   | $ | 35,606 |   | $ | 33,934 |   | $ | 33,037 |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
| Other                interest charges and                                                          |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
|                   amortization of debt discount,                                         |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
|                   premium, and expense, net                                              |   |     |   |                                        |   | **7,376**   |   |   | 6,716                                                                                                  |   |   | 1,949 |   |   | 3,113 |   |   | 3,674 |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                               |   |     |   |                                        | **$**  | **45,041**  |   | $      | 43,203                                                                                                 |   | $ | 37,555 |   | $ | 37,047 |   | $ | 36,711 |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                               |   |     |   |                                        |   |        |   |   |                                                                                                   |   |   |   |   |   |   |   |   |   |   |   |
| Ratio                of earnings to fixed charges                                                  |   | **2.91** |   |                                        | 2.82   |        |   | 3.53   |                                                                                                   |   | 4.53 |   |   | 5.71 |   |   |