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, 2007 were as follows:



|                                                                                                                                                                                                                                                                                                          |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |  | ----------------------- | --------- | - | ---- | - | --------- | ---- |  | - | ------- | - |  | ---- | ------- | - |  | - | ------- | -
|                                                                                                                                                                                                                                                                                                          |  | Year Ended December 31, |          
|                                                                                                                                                                                                                                                                                                          |  | 2007                    |           |   | 2006 |   |           | 2005 |  |   | 2004    |   |  | 2003 |        
|                                                                                                                                                                                                                                                                                                          |  | (dollars in thousands)  |          
|Earnings:                                                                                                                                                                                                                                                                                                 |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|Add:                                                                                                                                                                                                                                                                                                      |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|Income before minority interests in property partnerships, income 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 |  | $                       | 361,249   |   |      | $ | 298,767   |      |  | $ | 290,947 |   |  | $    | 290,984 |   |  | $ | 276,132 |  
|Gains on sales of real estate and other assets                                                                                                                                                                                                                                                            |  |                         | 957,406   |   |      |   | 727,131   |      |  |   | 188,546 |   |  |      | 9,822   |   |  |   | 70,627  |  
|Amortization of interest capitalized                                                                                                                                                                                                                                                                      |  |                         | 2,394     |   |      |   | 3,387     |      |  |   | 3,298   |   |  |      | 2,845   |   |  |   | 2,640   |  
|Distributions from unconsolidated joint ventures                                                                                                                                                                                                                                                          |  |                         | 7,157     |   |      |   | 8,206     |      |  |   | 7,179   |   |  |      | 6,663   |   |  |   | 8,412   |  
|Combined fixed charges and preferred distributions (see below)                                                                                                                                                                                                                                            |  |                         | 327,362   |   |      |   | 326,995   |      |  |   | 340,589 |   |  |      | 334,082 |   |  |   | 342,244 |  
|Subtract:                                                                                                                                                                                                                                                                                                 |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|Interest capitalized                                                                                                                                                                                                                                                                                      |  |                         | (31,046   | ) |      |   | (5,921    | )    |  |   | (5,718  | ) |  |      | (10,849 | ) |  |   | (19,200 | )
|Preferred distributions                                                                                                                                                                                                                                                                                   |  |                         | (10,429   | ) |      |   | (22,814   | )    |  |   | (26,780 | ) |  |      | (17,063 | ) |  |   | (23,608 | )
|                                                                                                                                                                                                                                                                                                          |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|Total earnings                                                                                                                                                                                                                                                                                            |  | $                       | 1,614,093 |   |      | $ | 1,335,751 |      |  | $ | 798,061 |   |  | $    | 616,484 |   |  | $ | 657,247 |  
|                                                                                                                                                                                                                                                                                                          |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|Fixed charges:                                                                                                                                                                                                                                                                                            |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|Interest expensed                                                                                                                                                                                                                                                                                         |  | $                       | 285,887   |   |      | $ | 298,260   |      |  | $ | 308,091 |   |  | $    | 306,170 |   |  | $ | 299,436 |  
|Interest capitalized                                                                                                                                                                                                                                                                                      |  |                         | 31,046    |   |      |   | 5,921     |      |  |   | 5,718   |   |  |      | 10,849  |   |  |   | 19,200  |  
|                                                                                                                                                                                                                                                                                                          |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|Total fixed charges                                                                                                                                                                                                                                                                                       |  | $                       | 316,933   |   |      | $ | 304,181   |      |  | $ | 313,809 |   |  | $    | 317,019 |   |  | $ | 318,636 |  
|                                                                                                                                                                                                                                                                                                          |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|Preferred distributions                                                                                                                                                                                                                                                                                   |  |                         | 10,429    |   |      |   | 22,814    |      |  |   | 26,780  |   |  |      | 17,063  |   |  |   | 23,608  |  
|                                                                                                                                                                                                                                                                                                          |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|Total combined fixed charges and preferred distributions                                                                                                                                                                                                                                                  |  | $                       | 327,362   |   |      | $ | 326,995   |      |  | $ | 340,589 |   |  | $    | 334,082 |   |  | $ | 342,244 |  
|                                                                                                                                                                                                                                                                                                          |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|Ratio of earnings to fixed charges                                                                                                                                                                                                                                                                        |  |                         | 5.09      |   |      |   | 4.39      |      |  |   | 2.54    |   |  |      | 1.94    |   |  |   | 2.06    |  
|                                                                                                                                                                                                                                                                                                          |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |  
|Ratio of earnings to combined fixed charges and preferred distributions                                                                                                                                                                                                                                   |  |                         | 4.93      |   |      |   | 4.08      |      |  |   | 2.34    |   |  |      | 1.85    |   |  |   | 1.92    |  
|                                                                                                                                                                                                                                                                                                          |  |                         |           |   |      |   |           |      |  |   |         |   |  |      |         |   |  |   |         |