Exhibit 12.3

Ameren Illinois Company

(Formerly known as Central Illinois Public Service Company)

Computation of Ratio of Earnings to Fixed Charges and Combined

Fixed Charges and Preferred Stock Dividend Requirements

(Thousands of Dollars, Except Ratios)

	Nine Months Ended September 30, 2010		Year Ended December 31, 2009
Net income from continuing operations	$	47,905	$	28,897
Add- Taxes based on income		31,663		16,265
Net income before income taxes		79,568		45,162
Add- fixed charges:
Interest on short-term and long-term debt (a)		20,504		28,315
Estimated interest cost within rental expense		933		1,216
Amortization of net debt premium, discount, and expenses		567		881
Total fixed charges		22,004		30,412
Earnings available for fixed charges		101,572		75,574
Ratio of earnings to fixed charges		4.61		2.48
Earnings required for combined fixed charges and preferred stock dividends:
Preferred stock dividends		1,884		2,512
Adjustment to pretax basis		1,245		1,414
		3,129		3,926
Combined fixed charges and preferred stock dividend requirements	$	25,133	$	34,338
Ratio of earnings to combined fixed charges and preferred stock dividend requirements		4.04		2.20

^(a) Includes interest expense related to uncertain tax positions