Erp Operating LTD Partnership 8-K Other Events

Exhibit 12

ERP OPERATING LIMITED PARTNERSHIP

Computation of Ratio of Earnings to Combined Fixed Charges

	Nine Months Ended September 30,						Year Ended December 31,
	2008			2007			2007			2006			2005			2004			2003
Income from continuing operations	$	106,091		$	38,612		$	73,580		$	34,617		$	102,080		$	45,376		$	55,361
Interest expense incurred, net		355,035			360,207			482,820			417,576			351,866			296,315			275,913
Amortization of deferred financing costs		6,751			7,853			10,121			8,077			6,338			5,676			4,958
Earnings before combined fixed charges and preferred distributions		467,877			406,672			566,521			460,270			460,284			347,367			336,232
Preference Unit distributions		(10,887	)		(19,157	)		(22,792	)		(37,113	)		(49,642	)		(53,746	)		(76,435	)
Premium on redemption of Preference Units		—			(6,144	)		(6,154	)		(3,965	)		(4,359	)		—			(20,237	)
Preference Interest and Junior Preference Unit distributions		(11	)		(437	)		(441	)		(2,002	)		(7,606	)		(19,490	)		(20,536	)
Premium on redemption of Preference Interests		—			—			—			(684	)		(4,134	)		(1,117	)		—
Earnings before combined fixed charges	$	456,979		$	380,934		$	537,134		$	416,506		$	394,543		$	273,014		$	219,024
Interest expense incurred, net	$	355,035		$	360,207		$	482,820		$	417,576		$	351,866		$	296,315		$	275,913
Amortization of deferred financing costs		6,751			7,853			10,121			8,077			6,338			5,676			4,958
Interest capitalized for real estate and unconsolidated entities under development		45,117			30,753			45,107			20,734			13,701			13,969			20,647
Amortization of deferred financing costs for real estate under development		1,509			755			1,521			46			—			—			—
Total combined fixed charges		408,412			399,568			539,569			446,433			371,905			315,960			301,518
Preference Unit distributions		10,887			19,157			22,792			37,113			49,642			53,746			76,435
Premium on redemption of Preference Units		—			6,144			6,154			3,965			4,359			—			20,237
Preference Interest and Junior Preference Unit distributions		11			437			441			2,002			7,606			19,490			20,536
Premium on redemption of Preference Interests		—			—			—			684			4,134			1,117			—
Total combined fixed charges and preferred distributions	$	419,310		$	425,306		$	568,956		$	490,197		$	437,646		$	390,313		$	418,726
Ratio of earnings before combined fixed charges to total combined fixed charges (1)		1.12			—			—			—			1.06			—			—
Ratio of earnings before combined fixed charges and preferred distributions to total combined fixed charges and preferred distributions (1)		1.12			—			—			—			1.05			—			—

(1) For the nine months ended September 30, 2007, the coverage deficiencies on both ratios approximated $18.6 million. For the years ended December 31, 2007, 2006, 2004 and 2003, the coverage deficiencies on both ratios approximated $2.4 million, $29.9 million, $42.9 million and $82.5 million, respectively. All ratios have been reduced due to the disposition of properties which resulted in the inclusion of those properties in discontinued operations for all periods presented. For all periods presented, the ratios have been further reduced due to non-cash depreciation expense charges and premiums on the redemption of Preference Units and/or Preference Interests. The Operating Partnership was in compliance with its unsecured public debt covenants for all periods presented.

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