Exhibit 12

ERP OPERATING LIMITED PARTNERSHIP
Computation of Ratio of Earnings to Combined Fixed Charges

	12/31/03		12/31/02		12/31/01		12/31/00		12/31/99		ˆ
Income from continuing operations	$	246,216	$	273,702	$	337,074	$	302,428	$	254,025
Interest expense incurred, net	326,465		333,152		344,755		358,432		319,216
Amortization of deferred financing costs	6,164		5,617		4,978		5,015		3,852
Earnings before combined fixed charges and preferred distributions	578,845		612,471		686,807		665,875		577,093
Preferred distributions	96,971		97,151		106,119		111,941		113,196
Premium on redemption of preference units	20,237		—		5,324		—		—
Earnings before combined fixed charges	$	461,637	$	515,320	$	575,364	$	553,934	$	463,897
Interest expense incurred, net	$	326,465	$	333,152	$	344,755	$	358,432	$	319,216
Amortization of deferred financing costs	6,164		5,617		4,978		5,015		3,852
Interest capitalized for real estate and unconsolidated entities under development	20,647		27,167		28,174		17,650		8,134
Total combined fixed charges	353,276		365,936		377,907		381,097		331,202
Preferred distributions	96,971		97,151		106,119		111,941		113,196
Premium on redemption of preference units	20,237		—		5,324		—		—
Total combined fixed charges and preferred distributions	$	470,484	$	463,087	$	489,350	$	493,038	$	444,398
Ratio of earnings before combined fixed charges to total combined fixed charges	1.31		1.41		1.52		1.45		1.40
Ratio of earnings before combined fixed charges and preferred distributions to total combined fixed charges and preferred distributions	1.23		1.32		1.40		1.35		1.30