**Exhibit 12.1**

**Brandywine Operating Partnership, L.P.****Computation of Ratio of Earnings to Combined Fixed Charges****(in thousands)**

|                                                                               |   | **For the three months ended March 31,** |   | **For the years ended December 31,** |   |
|------------------------------------------------------------------------------------|--------|------------------------------------------|--------|--------------------------------------|--------|
|                                                                               |   | **2006**                                 |   | **2005**                             |   | **2005** |   | **2004** |   | **2003** |   | **2002** |   | **2001** |   |
|                                                                               |   |                                          |        |                                 |        |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |
| **Earnings before fixed charges:**                                                 |   |                                     |   |                                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| **Add:**                                                                           |   |                                     |   |                                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Income (loss) from continuing operations                                           |   | $                                        | (5,946 | )                                    | $      | 9,691 |   | $ | 41,976 |   | $ | 60,281 |   | $ | 85,126 |   | $ | 57,018 |   | $ | 27,222 |   |
| Minority interest – partners’ share of consolidated real estate ventures |   |                                     | (298   | )                                    |   | 51 |   |   | 154 |   |   | (205 | ) |   | — |   |   | — |   |   | — |   |
| Fixed charges – per below                                                     |   |                                     | 45,069 |                                 |   | 20,221 |   |   | 86,636 |   |   | 61,062 |   |   | 62,407 |   |   | 69,881 |   |   | 76,558 |   |
| **Less:**                                                                          |   |                                     |   |                                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Capitalized interest                                                               |   |                                     | (2,545 | )                                    |   | (1,772 | ) |   | (9,603 | ) |   | (3,030 | ) |   | (1,503 | ) |   | (2,949 | ) |   | (5,178 | ) |
|                                                                               |   |                                          |        |                                 |        |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |
| Earnings before fixed charges                                                      |   | $                                        | 36,280 |                                 | $      | 28,191 |   | $ | 119,163 |   | $ | 118,108 |   | $ | 146,030 |   | $ | 123,950 |   | $ | 98,602 |   |
|                                                                               |   |                                          |        |                                 |        |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |
|                                                                               |   |                                     |   |                                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| **Fixed charges and Preferred Distributions:**                                     |   |                                     |   |                                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Interest expense (including amortization)                                          |   | $                                        | 40,967 |                                 | $      | 17,797 |   | $ | 74,363 |   | $ | 55,061 |   | $ | 57,835 |   | $ | 63,522 |   | $ | 67,496 |   |
| Capitalized interest                                                               |   |                                     | 2,545  |                                 |   | 1,772 |   |   | 9,603 |   |   | 3,030 |   |   | 1,503 |   |   | 2,949 |   |   | 5,178 |   |
| Proportionate share of interest for unconsolidated real estate ventures            |   |                                     | 1,557  |                                 |   | 652 |   |   | 2,670 |   |   | 2,971 |   |   | 3,069 |   |   | 3,410 |   |   | 3,884 |   |
|                                                                               |   |                                          |        |                                 |        |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |
| Total Fixed Charges                                                                |   |                                     | 45,069 |                                 |   | 20,221 |   |   | 86,636 |   |   | 61,062 |   |   | 62,407 |   |   | 69,881 |   |   | 76,558 |   |
|                                                                               |   |                                     |   |                                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Ratio of earnings to combined fixed charges and preferred distributions            |   |                                     | 0.80   |                                 |   | 1.39 |   |   | 1.38 |   |   | 1.93 |   |   | 2.34 |   |   | 1.77 |   |   | 1.29 |   |
|                                                                               |   |                                          |        |                                 |        |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |

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