**Exhibit      12.3**

| **Central                Illinois Public Service Company****Computation                of Ratios of Earnings to Fixed Charges and Combined****Fixed                Charges and Preferred Stock Dividend Requirements****(Thousands                of Dollars, Except Ratios)** |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                                                                                                                                                                                                                                                                           |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                           |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                           |   | **3                Months Ended**  |   |   | **Year                Ended** |   |
|                                                                                                                                                                                                                                                                                |   | **March                31,**  |   |   | **December                31,** |   |
|                                                                                                                                                                                                                                                                           |   | **2007** |   |   | **2006** |   |
| Net                income from continuing operations                                                                                                                                                                                                                           | $ | 10,777 |   | $ | 37,372 |   |
| Add-                Taxes based on income                                                                                                                                                                                                                                      |   | 5,084 |   |   | 15,539 |   |
| Net                income before income taxes                                                                                                                                                                                                                                  |   | 15,861 |   |   | 52,911 |   |
|                                                                                                                                                                                                                                                                           |   |   |   |   |   |   |
| Add-                fixed charges:                                                                                                                                                                                                                                             |   |   |   |   |   |   |
| Interest                on long term debt                                                                                                                                                                                                                                      |   | 8,211 |   |   | 29,932 |   |
| Estimated                interest cost within rental expense                                                                                                                                                                                                                   |   | 255 |   |   | 726 |   |
| Amortization                of net debt premium, discount,and                expenses                                                                                                                                                                                          |   | 295 |   |   | 1,025 |   |
| Total                fixed charges                                                                                                                                                                                                                                             |   | 8,761 |   |   | 31,683 |   |
|                                                                                                                                                                                                                                                                           |   |   |   |   |   |   |
| Earnings                available for fixed charges                                                                                                                                                                                                                            |   | 24,622 |   |   | 84,594 |   |
|                                                                                                                                                                                                                                                                           |   |   |   |   |   |   |
| Ratio                of earnings to fixed charges                                                                                                                                                                                                                              |   | 2.81 |   |   | 2.67 |   |
|                                                                                                                                                                                                                                                                           |   |   |   |   |   |   |
| Earnings                required for combined fixedcharges                and preferred stock dividends:                                                                                                                                                                       |   |   |   |   |   |   |
| Preferred                stock dividends                                                                                                                                                                                                                                       |   | 628 |   |   | 2,512 |   |
| Adjustment                to pre-tax basis                                                                                                                                                                                                                                     |   | 296 |   |   | 1,045 |   |
|                                                                                                                                                                                                                                                                           |   | 924 |   |   | 3,557 |   |
|                                                                                                                                                                                                                                                                           |   |   |   |   |   |   |
| Combined                fixed charges and preferred stockdividend                requirements                                                                                                                                                                                  | $ | 9,685 |   | $ | 35,240 |   |
|                                                                                                                                                                                                                                                                           |   |   |   |   |   |   |
| Ratio                of earnings to combined fixed chargesand                preferred stock dividend requirements                                                                                                                                                             |   | 2.54 |   |   | 2.40 |   |