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Exhibit 12.1


Corporate Office Properties Trust

Ratio of Earnings to Combined Fixed Charges and Preferred Share Dividends

(Dollars in thousands)

 
  Years Ended December 31,  
Earnings:
  2010   2009   2008   2007   2006  

Income from continuing operations before equity in income (loss) of unconsolidated entities and income taxes

  $ 39,016   $ 60,907   $ 56,728   $ 30,840   $ 32,532  

Gain on sales of real estate, excluding discontinued operations

    2,840         1,682     3,108     889  

Combined fixed charges and preferred share dividends (from below)

    135,836     115,014     122,395     127,139     111,787  

Amortization of capitalized interest

    1,363     1,105     890     695     527  

Distributed income (loss) of equity investees

            (203 )   (224 )   26  

Subtract:

                               
 

Capitalized interest (from below)

    (16,524 )   (15,461 )   (18,312 )   (19,964 )   (14,766 )
   

Preferred share dividends included in fixed charges

    (16,102 )   (16,102 )   (16,102 )   (16,068 )   (15,404 )
   

Preferred unit distributions included in fixed charges

    (660 )   (660 )   (660 )   (660 )   (660 )
   

Issuance costs associated with redeemed preferred shares

                    (3,896 )
                       

Total earnings

  $ 145,769   $ 144,803   $ 146,418   $ 124,866   $ 111,035  
                       

Combined fixed charges and preferred share dividends:

                               

Interest expense on continuing operations

  $ 101,865   $ 82,187   $ 86,368   $ 88,070   $ 73,395  

Interest expense on discontinued operations

    263     233     553     1,950     3,045  

Capitalized interest (internal and external)

    16,524     15,461     18,312     19,964     14,766  

Amortization of debt issuance costs-capitalized

    19     30     32     138     237  

Interest included in rental expense

    403     341     368     289     384  

Preferred share dividends

    16,102     16,102     16,102     16,068     15,404  

Preferred unit distributions

    660     660     660     660     660  

Issuance costs associated with redeemed preferred shares

                    3,896  
                       

Total combined fixed charges and preferred share dividends

  $ 135,836   $ 115,014   $ 122,395   $ 127,139   $ 111,787  
                       

Ratio of earnings to combined fixed charges and preferred share dividends

    1.07     1.26     1.20     0.98     0.99  
                       

Deficiency

                    $ 2,273   $ 752  
                             



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Corporate Office Properties Trust Ratio of Earnings to Combined Fixed Charges and Preferred Share Dividends (Dollars in thousands)