Exhibit 12.1

Exelon Corporation

Ratio of Earnings to Fixed Charges

																Quarter
																Ended
	Years Ended December 31,															March 31,
	2007			2008			2009			2010			2011			2012
Pre-tax income from continuing operations		4,172			4,034			4,418			4,221			3,952			358
Plus: Loss from equity investees		106			26			27			—			1			22
Less: Capitalized interest		(46	)		(33	)		(55	)		(43	)		(57	)		(15	)
Preference security dividend requirements of consolidated subsidiaries		(6	)		(6	)		(7	)		(7	)		(6	)		(3	)
Pre-tax income from continuing operations after adjustment for income or loss from equity investees, capitalized interest and preference security dividend requirements		4,226			4,021			4,383			4,171			3,890			362
Fixed charges:
Interest expensed and capitalized, amortization of debt discount and premium on all indebtedness (a)		896			865			761			836			761			205
Interest component of rental expense (b)		290			289			230			241			237			49
Preference security dividend requirements of consolidated subsidiaries		6			6			7			7			6			3
Total fixed charges		1,192			1,160			998			1,084			1,004			257
Pre-tax income from continuing operations after adjustment for income or loss from equity investees, capitalized interest and preference security dividend requirements plus fixed charges		5,418			5,181			5,381			5,255			4,894			619
Ratio of earnings to fixed charges		4.5			4.5			5.4			4.8			4.9			2.4

(a) Includes interest expense of $4 million for the quarter ended March 31, 2012 and $1 million, $109 million, $7 million, $0 and $13 million for the years ended December 31, 2011, 2010, 2009, 2008 and 2007, respectively, related to uncertain income tax positions.

(b) Represents one-third of rental expense relating to operating leases, which is a reasonable approximation of the interest factor.