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.