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)



|                                                                                      |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    
|------------------------------------------------------------------------------------- |  | ----------------------- | ------ | ---- | - | ------ |  | ---- | ------ |  | ---- | ------ | --- |  | - | ------ | ---
|                                                                                      |  | Year Ended December 31, |       
|                                                                                      |  | 2004                    |        | 2005 |   | 2006   |  | 2007 |        |  | 2008 |       
|Net income from continuing operations                                                 |  | $                       | 32,463 |      | $ | 42,998 |  | $    | 37,372 |  | $    | 16,535 |     |  | $ | 14,739 |    
|Add- Taxes based on income                                                            |  |                         | 16,135 |      |   | 24,596 |  |      | 15,539 |  |      | 9,322  |     |  |   | 5,199  |    
|                                                                                      |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    
|Net income before income taxes                                                        |  |                         | 48,598 |      |   | 67,594 |  |      | 52,911 |  |      | 25,857 |     |  |   | 19,938 |    
|Add- fixed charges:                                                                   |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    
|Interest on long term debt                                                            |  |                         | 31,372 |      |   | 28,969 |  |      | 29,932 |  |      | 36,670 | (1) |  |   | 29,422 | (1)
|Estimated interest cost within rental expense                                         |  |                         |       |      |   |       |  |      | 726    |  |      | 899    |     |  |   | 760    |    
|Amortization of net debt premium, discount, and expenses                              |  |                         | 903    |      |   | 953    |  |      | 1,025  |  |      | 1,105  |     |  |   | 1,024  |    
|                                                                                      |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    
|Total fixed charges                                                                   |  |                         | 32,275 |      |   | 29,922 |  |      | 31,683 |  |      | 38,674 |     |  |   | 31,206 |    
|                                                                                      |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    
|Earnings available for fixed charges                                                  |  |                         | 80,873 |      |   | 97,516 |  |      | 84,594 |  |      | 64,531 |     |  |   | 51,144 |    
|                                                                                      |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    
|Ratio of earnings to fixed charges                                                    |  |                         | 2.50   |      |   | 3.25   |  |      | 2.67   |  |      | 1.66   |     |  |   | 1.63   |    
|                                                                                      |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    
|Earnings required for combined fixed charges and preferred stock dividends:           |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    
|Preferred stock dividends                                                             |  |                         | 2,512  |      |   | 2,512  |  |      | 2,512  |  |      | 2,512  |     |  |   | 2,512  |    
|Adjustment to pre-tax basis                                                           |  |                         | 1,248  |      |   | 1,437  |  |      | 1,045  |  |      | 1,416  |     |  |   | 886    |    
|                                                                                      |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    
|                                                                                      |  |                         | 3,760  |      |   | 3,949  |  |      | 3,557  |  |      | 3,928  |     |  |   | 3,398  |    
|                                                                                      |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    
|Combined fixed charges and preferred stock dividend requirements                      |  | $                       | 36,035 |      | $ | 33,871 |  | $    | 35,240 |  | $    | 42,602 |     |  | $ | 34,604 |    
|                                                                                      |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    
|Ratio of earnings to combined fixed charges and preferred stock dividend requirements |  |                         | 2.24   |      |   | 2.87   |  |      | 2.40   |  |      | 1.51   |     |  |   | 1.47   |    
|                                                                                      |  |                         |        |      |   |        |  |      |        |  |      |        |     |  |   |        |    

(1)Includes FIN 48 interest expense