EXHIBIT 12.1

Omeros Corporation

Computation of Deficiency in the Coverage of Fixed
Charges by Earnings Before Fixed Charges



|                                                                       |  |                                   |        |   |                         |   |         |      |  |   |         |   |  |      |         |   |      |   |         |   |  |   |         |  
|---------------------------------------------------------------------- |  | --------------------------------- | ------ | - | ----------------------- | - | ------- | ---- |  | - | ------- | - |  | ---- | ------- | - | ---- | - | ------- | - |  | - | ------- | -
|                                                                       |  | For thethree monthsendedMarch 31, |        |   | Year Ended December 31, |  
|                                                                       |  | 2011                              |        |   | 2010                    |   |         | 2009 |  |   | 2008    |   |  | 2007 |         |   | 2006 |  
|                                                                       |  | (in thousands, except share data) |       
|Earnings before fixed charges:                                         |  |                                   |        |   |                         |   |         |      |  |   |         |   |  |      |         |   |      |   |         |   |  |   |         |  
|Loss from continuing operations before income taxes                    |  | $                                 | (6,542 | ) |                         | $ | (29,251 | )    |  | $ | (21,089 | ) |  | $    | (23,827 | ) |      | $ | (23,091 | ) |  | $ | (22,777 | )
|Add fixed charges                                                      |  |                                   | 369    |   |                         |   | 2,104   |      |  |   | 2,596   |   |  |      | 834     |   |      |   | 697     |   |  |   | 692     |  
|Add amortization of capitalized interest                               |  |                                   |       |   |                         |   |        |      |  |   |        |   |  |      |        |   |      |   |        |   |  |   |        |  
|Add distributed income of equity investees                             |  |                                   |       |   |                         |   |        |      |  |   |        |   |  |      |        |   |      |   |        |   |  |   |        |  
|Subtract capitalized interest                                          |  |                                   |       |   |                         |   |        |      |  |   |        |   |  |      |        |   |      |   |        |   |  |   |        |  
|                                                                       |  |                                   |        |   |                         |   |         |      |  |   |         |   |  |      |         |   |      |   |         |   |  |   |         |  
|Loss before fixed charges                                              |  | $                                 | (6,173 | ) |                         | $ | (27,147 | )    |  | $ | (18,493 | ) |  | $    | (22,993 | ) |      | $ | (22,394 | ) |  | $ | (22,085 | )
|                                                                       |  |                                   |        |   |                         |   |         |      |  |   |         |   |  |      |         |   |      |   |         |   |  |   |         |  
|                                                                       |  |                                   |        |   |                         |  
|Fixed Charges:                                                         |  |                                   |        |   |                         |   |         |      |  |   |         |   |  |      |         |   |      |   |         |   |  |   |         |  
|Interest expense                                                       |  | $                                 | 237    |   |                         | $ | 1,328   |      |  | $ | 1,948   |   |  | $    | 280     |   |      | $ | 151     |   |  | $ | 91      |  
|Amortization of debt expense                                           |  |                                   | 56     |   |                         |   | 503     |      |  |   | 254     |   |  |      | 55      |   |      |   |        |   |  |   |        |  
|Estimate of interest expense within rental expense                     |  |                                   | 76     |   |                         |   | 273     |      |  |   | 394     |   |  |      | 499     |   |      |   | 546     |   |  |   | 601     |  
|Preference security dividend requirements of consolidated subsidiaries |  |                                   |       |   |                         |   |        |      |  |   |        |   |  |      |        |   |      |   |        |   |  |   |        |  
|                                                                       |  |                                   |        |   |                         |   |         |      |  |   |         |   |  |      |         |   |      |   |         |   |  |   |         |  
|Total fixed charges                                                    |  | $                                 | 369    |   |                         | $ | 2,104   |      |  | $ | 2,596   |   |  | $    | 834     |   |      | $ | 697     |   |  | $ | 692     |  
|                                                                       |  |                                   |        |   |                         |   |         |      |  |   |         |   |  |      |         |   |      |   |         |   |  |   |         |  
|Deficiency of earnings available to cover fixed charges                |  |                                   | (6,542 | ) |                         |   | (29,251 | )    |  |   | (21,089 | ) |  |      | (23,827 | ) |      |   | (23,091 | ) |  |   | (22,777 | )