**Exhibit      12.1**| **Ameren                Corporation****Computation                of Ratio of Earnings to Fixed Charges****(Thousands                of Dollars, Except Ratios)** |                              |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------|
|                                                                                                                                                              |                              |   |   |   |   |
|                                                                                                                                                              |                              |   |   |   |   |
|                                                                                                                                                              | **6                Months Ended** |   |   | **Year                Ended** |   |
|                                                                                                                                                              | **June                30,**       |   |   | **December                31,** |   |
|                                                                                                                                                              | **2007**                          |   |   | **2006** |   |
| Net                income from continuing operations                                                                                                              | $                                 | 266,182 |   |   | $ | 546,738 |   |
| Less-                Change in accounting principle                                                                                                               |                              | - |   |   |   | - |   |
| Less-                Minority interest                                                                                                                            |                              | (13,109 | ) |   |   | (27,135 | ) |
| Add-                Taxes based on income                                                                                                                         |                              | 148,508 |   |   |   | 283,825 |   |
| Net                income before income taxes, change in accounting principle, and minority                interest                                               |                              | 427,799 |   |   |   | 857,698 |   |
|                                                                                                                                                              |                              |   |   |   |   |   |   |
| Add-                fixed charges:                                                                                                                                |                              |   |   |   |   |   |   |
| Interest                on long term debt                                                                                                                         |                              | 206,979 |   |   |   | 345,410 |   |
| Estimated                interest cost within rental expense                                                                                                      |                              | 2,175 |   |   |   | 4,081 |   |
| Amortization                of net debt premium, discount,and                expenses                                                                             |                              | 9,766 |   |   |   | 15,341 |   |
| Subsidiary                preferred stock dividends                                                                                                               |                              | 5,452 |   |   |   | 10,936 |   |
| Adjust                preferred stock dividends to pre-taxbasis                                                                                                   |                              | 2,981 |   |   |   | 5,565 |   |
| Total                fixed charges                                                                                                                                |                              | 227,353 |   |   |   | 381,333 |   |
| Less:                Adjustment of preferred stock dividends to pre-tax basis                                                                                     |                              | 2,981 |   |   |   | 5,565 |   |
|                                                                                                                                                              |                              |   |   |   |   |   |   |
| Earnings                available for fixed charges                                                                                                               | $                                 | 652,171 |   |   | $ | 1,233,466 |   |
|                                                                                                                                                              |                              |   |   |   |   |   |   |
| Ratio                of earnings to fixed charges                                                                                                                 |                              | 2.86 |   |   |   | 3.23 |   |