EXHIBIT 12.1

BOSTON PROPERTIES LIMITED PARTNERSHIP

CALCULATION OF RATIOS OF EARNINGS TO FIXED CHARGES

CALCULATION OF RATIOS OF EARNINGS TO COMBINED FIXED CHARGES AND PREFERRED DISTRIBUTIONS

Boston Properties Limited Partnerships ratios of earnings to fixed charges and ratios of earnings to combined fixed charges and preferred distributions for the
five years ended December 31, 2008 were as follows:



|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |  | ----------------------- | ------- | - | ---- | - | --------- | ---- |  | - | --------- | - |  | ---- | ------- | - |  | - | ------- | -
|                                                                                                                                                                                                                                                                                                                 |  | Year Ended December 31, |        
|                                                                                                                                                                                                                                                                                                                 |  | 2008                    |         |   | 2007 |   |           | 2006 |  |   | 2005      |   |  | 2004 |        
|                                                                                                                                                                                                                                                                                                                 |  | (dollars in thousands)  |        
|Earnings:                                                                                                                                                                                                                                                                                                        |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |     
|Add:                                                                                                                                                                                                                                                                                                             |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |     
|Income before minority interests in property partnerships, income (loss) from unconsolidated joint ventures, gains on sales of real estate and
other assets, discontinued operations, cumulative effect of a change in accounting principle and preferred distributions and allocation of undistributed earnings |  | $                       | 310,776 |   |      | $ | 361,249   |      |  | $ | 298,767   |   |  | $    | 290,947 |   |  | $ | 290,984 |  
|Gains on sales of real estate and other assets                                                                                                                                                                                                                                                                   |  |                         | 33,340  |   |      |   | 957,406   |      |  |   | 727,131   |   |  |      | 188,546 |   |  |   | 9,822   |  
|Amortization of interest capitalized                                                                                                                                                                                                                                                                             |  |                         | 2,315   |   |      |   | 2,394     |      |  |   | 3,387     |   |  |      | 3,298   |   |  |   | 2,845   |  
|Distributions from unconsolidated joint ventures                                                                                                                                                                                                                                                                 |  |                         | 5,988   |   |      |   | 7,157     |      |  |   | 8,206     |   |  |      | 7,179   |   |  |   | 6,663   |  
|Combined fixed charges and preferred distributions (see below)                                                                                                                                                                                                                                                   |  |                         | 318,081 |   |      |   | 327,362   |      |  |   | 326,995   |   |  |      | 340,589 |   |  |   | 334,082 |  
|Subtract:                                                                                                                                                                                                                                                                                                        |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|Interest capitalized                                                                                                                                                                                                                                                                                             |  |                         | (41,883 | ) |      |   | (31,046   | )    |  |   | (5,921    | ) |  |      | (5,718  | ) |  |   | (10,849 | )
|Preferred distributions                                                                                                                                                                                                                                                                                          |  |                         | (4,226  | ) |      |   | (10,429   | )    |  |   | (22,814   | ) |  |      | (26,780 | ) |  |   | (17,063 | )
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|Total earnings                                                                                                                                                                                                                                                                                                   |  | $                       | 624,391 |   |      | $ | 1,614,093 |      |  | $ | 1,335,751 |   |  | $    | 798,061 |   |  | $ | 616,484 |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |     
|Fixed charges:                                                                                                                                                                                                                                                                                                   |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|Interest expensed                                                                                                                                                                                                                                                                                                |  | $                       | 271,972 |   |      | $ | 285,887   |      |  | $ | 298,260   |   |  | $    | 308,091 |   |  | $ | 306,170 |  
|Interest capitalized                                                                                                                                                                                                                                                                                             |  |                         | 41,883  |   |      |   | 31,046    |      |  |   | 5,921     |   |  |      | 5,718   |   |  |   | 10,849  |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|Total fixed charges                                                                                                                                                                                                                                                                                              |  | $                       | 313,855 |   |      | $ | 316,933   |      |  | $ | 304,181   |   |  | $    | 313,809 |   |  | $ | 317,019 |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |     
|Preferred distributions                                                                                                                                                                                                                                                                                          |  |                         | 4,226   |   |      |   | 10,429    |      |  |   | 22,814    |   |  |      | 26,780  |   |  |   | 17,063  |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|Total combined fixed charges and preferred distributions                                                                                                                                                                                                                                                         |  | $                       | 318,081 |   |      | $ | 327,362   |      |  | $ | 326,995   |   |  | $    | 340,589 |   |  | $ | 334,082 |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |     
|Ratio of earnings to fixed charges                                                                                                                                                                                                                                                                               |  |                         | 1.99    |   |      |   | 5.09      |      |  |   | 4.39      |   |  |      | 2.54    |   |  |   | 1.94    |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |     
|Ratio of earnings to combined fixed charges and preferred distributions                                                                                                                                                                                                                                          |  |                         | 1.96    |   |      |   | 4.93      |      |  |   | 4.08      |   |  |      | 2.34    |   |  |   | 1.85    |  
|                                                                                                                                                                                                                                                                                                                 |  |                         |         |   |      |   |           |      |  |   |           |   |  |      |         |   |  |   |         |