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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,  
 
   2009   2008   2007   2006   2005  

Earnings:

                                

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

   $ 61,094   $ 56,902   $ 30,992   $ 32,708   $ 38,114  

Gain on sales of real estate, excluding discontinued operations

     —     1,682     3,108     889     366  

Combined fixed charges and preferred share dividends (from below)

     115,014     122,395     127,139     111,787     85,240  

Amortization of capitalized interest

     1,105     890     695     527     337  

Distributed income (loss) of equity investees

     —     (203 )   (224 )   26     (164 )

Subtract:

                                
 

Capitalized interest (from below)

     (15,461 )   (18,312 )   (19,964 )   (14,766 )   (9,871 )
 

Preferred share dividends included in fixed charges

     (16,102 )   (16,102 )   (16,068 )   (15,404 )   (14,615 )
 

Preferred unit distributions included in fixed charges

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

Issuance costs associated with redeemed preferred shares

     —     —     —     (3,896 )   —  
                       

Total earnings

   $ 144,990   $ 146,592   $ 125,018   $ 111,211   $ 98,747  
                       

Combined fixed charges and preferred share dividends:

                                

Interest expense on continuing operations

   $ 82,208   $ 86,414   $ 88,130   $ 73,442   $ 55,077  

Interest expense on discontinued operations

     212     507     1,890     2,998     4,307  

Capitalized interest (internal and external)

     15,461     18,312     19,964     14,766     9,871  

Amortization of debt issuance costs—capitalized

     30     32     138     237     272  

Interest included in rental expense

     341     368     289     384     438  

Preferred share dividends

     16,102     16,102     16,068     15,404     14,615  

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

   $ 115,014   $ 122,395   $ 127,139   $ 111,787   $ 85,240  
                       

Ratio of earnings to combined fixed charges and preferred share dividends

     1.26     1.20     0.98     0.99     1.16  
                       



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