**Exhibit 12**

 

**ERP OPERATING LIMITED PARTNERSHIPComputation of Ratio of Earnings to Combined Fixed Charges**

 
|                                                                                                                                          |   | **03/31/04** |        | **03/31/03** |       | **12/31/03** |       | **12/31/02** |        | **12/31/01** |       | **12/31/00** |       | **12/31/99** |        |
|-----------------------------------------------------------------------------------------------------------------------------------------------|--------|--------------|-------------|--------------|------------|--------------|------------|--------------|-------------|--------------|------------|--------------|------------|--------------|-------------|
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| Income from continuing operations                                                                                                             |   | $            | 55,021      |         | $          | 60,932       |       | $            | 246,216     |         | $          | 273,702      |       | $            | 337,074     |   | $ | 302,428 |   | $ | 254,025 |   |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| Interest expense incurred, net                                                                                                                |   | 79,858       |        | 79,417       |       | 326,465      |       | 333,152      |        | 344,755      |       | 358,432      |       | 319,216      |        |
| Amortization of deferred financing costs                                                                                                      |   | 1,426        |        | 1,338        |       | 6,164        |       | 5,617        |        | 4,978        |       | 5,015        |       | 3,852        |        |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| **Earnings before combined fixed charges and  preferred distributions**                                                                       |   | **136,305**  | ** **  | **141,687**  | ** ** | **578,845**  | ** ** | **612,471**  | ** **  | **686,807**  | ** ** | **665,875**  | ** ** | **577,093**  | ** **  |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| Preferred distributions                                                                                                                       |   | 18,756       |        | 24,180       |       | 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**                                                                                                    |   | **$**        | **117,549** | ** **   | **$**      | **117,507**  | ** ** | **$**        | **461,637** | ** **   | **$**      | **515,320**  | ** ** | **$**        | **575,364** | ** ** | **$** | **553,934** | ** ** | **$** | **463,897** | ** ** |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| Interest expense incurred, net                                                                                                                |   | $            | 79,858      |         | $          | 79,417       |       | $            | 326,465     |         | $          | 333,152      |       | $            | 344,755     |   | $ | 358,432 |   | $ | 319,216 |   |
| Amortization of deferred financing costs                                                                                                      |   | 1,426        |        | 1,338        |       | 6,164        |       | 5,617        |        | 4,978        |       | 5,015        |       | 3,852        |        |
| Interest capitalized for real estate and  unconsolidated entities under development                                                           |   | 2,652        |        | 5,437        |       | 20,647       |       | 27,167       |        | 28,174       |       | 17,650       |       | 8,134        |        |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| **Total combined fixed charges**                                                                                                              |   | **83,936**   | ** **  | **86,192**   | ** ** | **353,276**  | ** ** | **365,936**  | ** **  | **377,907**  | ** ** | **381,097**  | ** ** | **331,202**  | ** **  |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| Preferred distributions                                                                                                                       |   | 18,756       |        | 24,180       |       | 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**                                                                                 |   | **$**        | **102,692** | ** **   | **$**      | **110,372**  | ** ** | **$**        | **470,484** | ** **   | **$**      | **463,087**  | ** ** | **$**        | **489,350** | ** ** | **$** | **493,038** | ** ** | **$** | **444,398** | ** ** |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| **Ratio of earnings before combined fixed  charges to total combined fixed charges**                                                          |   | **1.40**     | ** **  | **1.36**     | ** ** | **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** |   | **1.33**     | ** **  | **1.28**     | ** ** | **1.23**     | ** ** | **1.32**     | ** **  | **1.40**     | ** ** | **1.35**     | ** ** | **1.30**     | ** **  |
|                                                                                                                                               |        |              |             |              |            |              |            |              |             |              |            |              |            |              |             |  |  |  |  |  |  |  |  |

 

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