Exhibit 12

PS BUSINESS PARKS, INC.

EXHIBIT 12
STATEMENT RE: COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES
(Unaudited, in thousands, except ratio data)


	For the Three Months				For the Nine Months
	Ended September 30,				Ended September 30,
	2011		2010		2011			2010
Income from continuing operations	$	27,836	$	23,456	$	77,509		$	72,357
Interest expense		1,261		875		3,621			2,586

Earnings from continuing operations available to cover fixed charges	$	29,097	$	24,331	$	81,130		$	74,943

Fixed charges ⁽¹⁾	$	1,261	$	875	$	3,621		$	2,586
Preferred stock dividends		10,450		10,080		31,349			33,958
Preferred partnership distributions		99		984		(7,091	)		4,118

Combined fixed charges and preferred distributions	$	11,810	$	11,939	$	27,879		$	40,662

Ratio of earnings from continuing operations to fixed charges		23.1		27.8		22.4			29.0

Ratio of earnings from continuing operations to combined fixed charges and preferred distributions		2.5		2.0		2.9			1.8


	For the Years Ended December 31,
	2010		2009			2008		2007		2006
Income from continuing operations	$	96,401	$	91,442		$	84,188	$	80,683	$	77,707
Interest expense		3,534		3,552			3,952		4,130		2,575

Earnings from continuing operations available to cover fixed charges	$	99,935	$	94,994		$	88,140	$	84,813	$	80,282

Fixed charges ⁽¹⁾	$	3,534	$	3,552		$	3,952	$	4,130	$	2,575
Preferred stock dividends		46,214		17,440			46,630		50,937		47,933
Preferred partnership distributions		5,103		(2,569	)		7,007		6,854		11,155

Combined fixed charges and preferred distributions	$	54,851	$	18,423		$	57,589	$	61,921	$	61,663

Ratio of earnings from continuing operations to fixed charges		28.3		26.7			22.3		20.5		31.2

Ratio of earnings from continuing operations to combined fixed charges and preferred distributions		1.8		5.2			1.5		1.4		1.3


⁽¹⁾		Fixed charges include interest expense.

PS BUSINESS PARKS, INC.

EXHIBIT 12
STATEMENT RE: COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

(Unaudited, in thousands, except ratio data)

Supplemental Disclosure of Ratio of Funds from Operations (“FFO”) to Fixed Charges:


	For the Three Months				For the Nine Months
	Ended September 30,				Ended September 30,
	2011		2010		2011			2010
FFO	$	38,783	$	33,695	$	116,971		$	92,717
Interest expense		1,261		875		3,621			2,586
Net income allocable to noncontrolling interests — preferred units		99		984		(7,091	)		4,118
Preferred stock dividends		10,450		10,080		31,349			33,958

FFO available to cover fixed charges	$	50,593	$	45,634	$	144,850		$	133,379

Fixed charges ⁽¹⁾	$	1,261	$	875	$	3,621		$	2,586
Preferred stock dividends ⁽²⁾		10,450		10,080		31,349			32,104
Preferred partnership distributions ⁽²⁾		99		984		298			3,536

Combined fixed charges and preferred distributions paid	$	11,810	$	11,939	$	35,268		$	38,226

Ratio of adjusted FFO to fixed charges		40.1		52.2		40.0			51.6

Ratio of adjusted FFO to combined fixed charges and preferred distributions paid		4.3		3.8		4.1			3.5


	For the Years Ended December 31,
	2010		2009			2008		2007		2006
FFO	$	124,420	$	163,074		$	131,558	$	122,405	$	106,235
Interest expense		3,534		3,552			3,952		4,130		2,575
Net income allocable to noncontrolling interests — preferred units		5,103		(2,569	)		7,007		6,854		11,155
Preferred stock dividends		46,214		17,440			46,630		50,937		47,933

FFO available to cover fixed charges	$	179,271	$	181,497		$	189,147	$	184,326	$	167,898

Fixed charges ⁽¹⁾	$	3,534	$	3,552		$	3,952	$	4,130	$	2,575
Preferred stock dividends ⁽²⁾		42,730		44,662			50,858		50,937		44,553
Preferred partnership distributions ⁽²⁾		4,521		5,848			7,007		6,854		9,789

Combined fixed charges and preferred distributions paid	$	50,785	$	54,062		$	61,817	$	61,921	$	56,917

Ratio of adjusted FFO to fixed charges		50.7		51.1			47.9		44.6		65.2

Ratio of adjusted FFO to combined fixed charges and preferred distributions paid		3.5		3.4			3.1		3.0		2.9


⁽¹⁾		Fixed charges include interest expense.

⁽²⁾		Excludes the issuance costs related to the redemption/repurchase of preferred equity and the gain on the repurchase of preferred equity.