EXHIBIT 12

CAPSTEAD MORTGAGE CORPORATION

COMPUTATION OF RATIO OF NET INCOME TO
COMBINED FIXED CHARGES AND

PREFERRED STOCK DIVIDENDS

(In thousands, except ratios)

(Unaudited)

Computation of ratio of net income to combined fixed charges and preferred
stock dividends:



|                                                                                                      |  |                               |                         |  |  |      |         |  |      |   |         |      |  |   |         |  |  |   |         |  |  |   |         | 
|----------------------------------------------------------------------------------------------------- |  | ----------------------------- | ----------------------- |  |  | ---- | ------- |  | ---- | - | ------- | ---- |  | - | ------- |  |  | - | ------- |  |  | - | ------- | 
|                                                                                                      |  | Six 
MonthsEndedJune 30, 2011 |                         |  |  |      |         |  |      |   |         |      |  |   |         |  |  |  
|                                                                                                      |  |                               | Year Ended December 31, | 
|                                                                                                      |  |                               | 2010                    |  |  | 2009 |         |  | 2008 |   |         | 2007 |  |   | 2006    | 
|Fixed charges                                                                                         |  | $                             | 30,407                  |  |  | $    | 56,251  |  |      | $ | 128,830 |      |  | $ | 258,453 |  |  | $ | 275,648 |  |  | $ | 235,521 | 
|Preferred stock dividends                                                                             |  |                               | 10,118                  |  |  |      | 20,233  |  |      |   | 20,239  |      |  |   | 20,251  |  |  |   | 20,256  |  |  |   | 20,256  | 
|                                                                                                      |  |                               |                         |  |  |      |         |  |      |   |         |      |  |   |         |  |  |   |         |  |  |   |         | 
|Combined fixed charges andpreferred stock dividends                                                   |  | $                             | 40,525                  |  |  | $    | 76,484  |  |      | $ | 149,069 |      |  | $ | 278,704 |  |  | $ | 295,904 |  |  | $ | 255,777 | 
|                                                                                                      |  |                               |                         |  |  |      |         |  |      |   |         |      |  |   |         |  |  |   |         |  |  |   |         | 
|Fixed charges                                                                                         |  | $                             | 30,407                  |  |  | $    | 56,251  |  |      | $ | 128,830 |      |  | $ | 258,453 |  |  | $ | 275,648 |  |  | $ | 235,521 | 
|Net income                                                                                            |  |                               | 77,233                  |  |  |      | 126,896 |  |      |   | 129,263 |      |  |   | 125,923 |  |  |   | 24,713  |  |  |   | 3,843   | 
|                                                                                                      |  |                               |                         |  |  |      |         |  |      |   |         |      |  |   |         |  |  |   |         |  |  |   |         | 
|                                                                                                      |  | $                             | 107,640                 |  |  | $    | 183,147 |  |      | $ | 258,093 |      |  | $ | 384,376 |  |  | $ | 300,361 |  |  | $ | 239,364 | 
|                                                                                                      |  |                               |                         |  |  |      |         |  |      |   |         |      |  |   |         |  |  |   |         |  |  |   |         | 
|Ratio of net income to combined fixed charges andpreferred stock dividends                            |  |                               | 2.66:1                  |  |  |      | 2.39:1  |  |      |   | 1.73:1  |      |  |   | 1.38:1  |  |  |   | 1.02:1  |  |  |   |         | 
|                                                                                                      |  |                               |                         |  |  |      |         |  |      |   |         |      |  |   |         |  |  |   |         |  |  |   |         | 
|Deficiency of net income (before fixed charges) tocombined fixed charges and preferred stockdividends |  |                               |                         |  |  |      |         |  |      |   |         |      |  |   |         |  |  |   |         |  |  | $ | 16,413  | 
|                                                                                                      |  |                               |                         |  |  |      |         |  |      |   |         |      |  |   |         |  |  |   |         |  |  |   |         |