EXHIBIT 12.1

Corporate Office Properties Trust

Ratio of Earnings to Combined Fixed Charges and Preferred Share Dividends

(Dollars in thousands)

		Years Ended December 31,
		2015				2014				2013				2012				2011
Earnings:
Income (loss) from continuing operations before equity in income (loss) of unconsolidated entities and income taxes		$	120,812			$	34,590			$	36,704			$	8,894			$	(85,580	)
Gain on sales of real estate, excluding discontinued operations		68,047				10,671				9,016				21				2,732
Combined fixed charges and preferred share dividends (from below)		111,737				115,842				120,307				133,345				139,159
Amortization of capitalized interest		2,591				2,374				1,977				1,798				1,610
Distributed income (loss) of equity investees		361				225				1,857				—				(31		)
Subtract:
Capitalized interest (from below)		(7,151		)		(6,065		)		(8,785		)		(13,903		)		(17,400		)
Preferred share dividends included in fixed charges		(14,210		)		(15,939		)		(19,971		)		(20,844		)		(16,102		)
Preferred unit distributions included in fixed charges		(660		)		(660		)		(660		)		(660		)		(660		)
Preferred distributions of other consolidated entities		(16		)		(16		)		(16		)		(16		)		—
Total earnings		$	281,511			$	141,022			$	140,429			$	108,635			$	23,728
Combined Fixed Charges and Preferred Share Dividends:
Combined fixed charges and preferred share dividends:
Interest expense on continuing operations		$	89,074			$	92,393			$	82,010			$	86,401			$	90,037
Interest expense on discontinued operations		—				—				8,221				10,397				14,264
Capitalized interest (internal and external)		7,151				6,065				8,785				13,903				17,400
Amortization of debt issuance costs-capitalized		8				186				144				649				183
Interest included in rental expense		618				583				500				475				513
Preferred share dividends		14,210				15,939				19,971				20,844				16,102
Preferred unit distributions		660				660				660				660				660
Preferred distributions of other consolidated entities		16				16				16				16				—
Total combined fixed charges and preferred share dividends		$	111,737			$	115,842			$	120,307			$	133,345			$	139,159
Ratio of earnings to combined fixed charges and preferred share dividends		2.52				1.22				1.17				0.81				0.17
														$	24,710			$	115,431

For purposes of calculating the above ratios, earnings were computed by adding fixed charges (excluding capitalized interest), gain on sales of real estate (excluding discontinued operations) amortization of capitalized interest and distributed income (loss) of equity investees to income (loss) from continuing operations before noncontrolling interests, equity in income (loss) of unconsolidated entities and income taxes. Fixed charges consist of interest costs and capitalized amortization of debt issuance costs.