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)



|                                                                                      |  |                                 |        |                                  |   |       
|------------------------------------------------------------------------------------- |  | ------------------------------- | ------ | -------------------------------- | - | ------
|                                                                                      |  | Three Months EndedMarch 31,2009 |        | Year
Ended      December 31,2008
|Net income from continuing operations                                                 |  | $                               | 6,838  |                                  | $ | 14,739
|Add- Taxes based on income                                                            |  |                                 | 3,518  |                                  |   | 5,199 
|                                                                                      |  |                                 |        |                                  |   |       
|Net income before income taxes                                                        |  |                                 | 10,356 |                                  |   | 19,938
|Add- fixed charges:                                                                   |  |                                 |        |                                  |   |       
|Interest on long term debt(1)                                                         |  |                                 | 6,949  |                                  |   | 29,422
|Estimated interest cost within rental expense                                         |  |                                 | 264    |                                  |   | 760   
|Amortization of net debt premium, discount, and expenses                              |  |                                 | 252    |                                  |   | 1,024 
|                                                                                      |  |                                 |        |                                  |   |       
|Total fixed charges                                                                   |  |                                 | 7,465  |                                  |   | 31,206
|                                                                                      |  |                                 |        |                                  |   |       
|Earnings available for fixed charges                                                  |  |                                 | 17,821 |                                  |   | 51,144
|                                                                                      |  |                                 |        |                                  |   |       
|Ratio of earnings to fixed charges                                                    |  |                                 | 2.38   |                                  |   | 1.63  
|                                                                                      |  |                                 |        |                                  |   |       
|Earnings required for combined fixed charges and preferred stock dividends:           |  |                                 |        |                                  |   |       
|Preferred stock dividends                                                             |  |                                 | 628    |                                  |   | 2,512 
|Adjustment to pretax basis                                                            |  |                                 | 323    |                                  |   | 886   
|                                                                                      |  |                                 |        |                                  |   |       
|                                                                                      |  |                                 | 951    |                                  |   | 3,398 
|                                                                                      |  |                                 |        |                                  |   |       
|Combined fixed charges and preferred stock dividend requirements                      |  | $                               | 8,416  |                                  | $ | 34,604
|                                                                                      |  |                                 |        |                                  |   |       
|Ratio of earnings to combined fixed charges and preferred stock dividend requirements |  |                                 | 2.11   |                                  |   | 1.47  
|                                                                                      |  |                                 |        |                                  |   |       



|(1) | Includes FIN 48 interest expense
|--- | --------------------------------