**Exhibit 12**

** **

**ERP OPERATING LIMITED PARTNERSHIP**

**Computation of Ratio of Earnings to CombinedFixed Charges**

** **
|                                                                                                                                          |   | **06/30/04** |        | **06/30/03** |       | **12/31/03** |       | **12/31/02** |        | **12/31/01** |       | **12/31/00** |       | **12/31/99** |        |
|-----------------------------------------------------------------------------------------------------------------------------------------------|--------|--------------|-------------|--------------|------------|--------------|------------|--------------|-------------|--------------|------------|--------------|------------|--------------|-------------|
| Income from continuing operations                                                                                                             |   | $            | 110,668     |         | $          | 123,233      |       | $            | 236,150     |         | $          | 261,762      |       | $            | 321,309     |   | $ | 287,221 |   | $ | 240,364 |   |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| Interest expense incurred, net                                                                                                                |   | 166,338      |        | 162,380      |       | 325,191      |       | 331,489      |        | 342,712      |       | 354,916      |       | 316,875      |        |
| Amortization of deferred financing costs                                                                                                      |   | 3,127        |        | 2,897        |       | 6,081        |       | 5,587        |        | 4,912        |       | 4,959        |       | 3,797        |        |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| **Earnings before combined fixed charges and  preferred distributions**                                                                       |   | **280,133**  | ** **  | **288,510**  | ** ** | **567,422**  | ** ** | **598,838**  | ** **  | **668,933**  | ** ** | **647,096**  | ** ** | **561,036**  | ** **  |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| Preferred distributions                                                                                                                       |   | 37,493       |        | 48,417       |       | 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**                                                                                                    |   | **$**        | **242,640** | ** **   | **$**      | **240,093**  | ** ** | **$**        | **450,214** | ** **   | **$**      | **501,687**  | ** ** | **$**        | **557,490** | ** ** | **$** | **535,155** | ** ** | **$** | **447,840** | ** ** |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| Interest expense incurred, net                                                                                                                |   | $            | 166,338     |         | $          | 162,380      |       | $            | 325,191     |         | $          | 331,489      |       | $            | 342,712     |   | $ | 354,916 |   | $ | 316,875 |   |
| Amortization of deferred financing costs                                                                                                      |   | 3,127        |        | 2,897        |       | 6,081        |       | 5,587        |        | 4,912        |       | 4,959        |       | 3,797        |        |
| Interest capitalized for real estate and  unconsolidated entities under development                                                           |   | 6,850        |        | 10,923       |       | 20,647       |       | 27,167       |        | 28,174       |       | 17,650       |       | 8,134        |        |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| **Total combined fixed charges**                                                                                                              |   | **176,315**  | ** **  | **176,200**  | ** ** | **351,919**  | ** ** | **364,243**  | ** **  | **375,798**  | ** ** | **377,525**  | ** ** | **328,806**  | ** **  |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| Preferred distributions                                                                                                                       |   | 37,493       |        | 48,417       |       | 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**                                                                                 |   | **$**        | **213,808** | ** **   | **$**      | **224,617**  | ** ** | **$**        | **469,127** | ** **   | **$**      | **461,394**  | ** ** | **$**        | **487,241** | ** ** | **$** | **489,466** | ** ** | **$** | **442,002** | ** ** |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| **Ratio of earnings before combined fixed  charges to total combined fixed charges**                                                          |   | **1.38**     | ** **  | **1.36**     | ** ** | **1.28**     | ** ** | **1.38**     | ** **  | **1.48**     | ** ** | **1.42**     | ** ** | **1.36**     | ** **  |
|                                                                                                                                          |   |         |        |         |       |         |       |         |        |         |       |         |       |         |        |
| **Ratio of earnings before combined fixed  charges and preferred distributions to total combined fixed charges and  preferred distributions** |   | **1.31**     | ** **  | **1.28**     | ** ** | **1.21**     | ** ** | **1.30**     | ** **  | **1.37**     | ** ** | **1.32**     | ** ** | **1.27**     | ** **  |
|                                                                                                                                               |        |              |             |              |            |              |            |              |             |              |            |              |            |              |             |  |  |  |  |  |  |  |  |

 

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