Exhibit 12(a)
                                           Aon Corporation and Consolidated Subsidiaries
                                             Combined With Unconsolidated Subsidiaries
                                         Computation of Ratio of Earnings to Fixed Charges


                                                 Nine Months
                                                Ended Sept 30,                       Years Ended December 31,
                                          ------------------------  --------------------------------------------------------------- 
(millions except ratios)                      1996         1995         1995         1994         1993       1992 (1)       1991
                                          -----------  -----------  -----------  -----------  -----------  -----------  ----------- 

Income from continuing operations
                                                                                                          
   before provision for income taxes      $    374.9   $    360.9   $    458.0   $    397.0   $    331.6   $    179.1   $    242.4

Add back fixed charges:

Interest on indebtedness                        32.9         41.2         55.5         46.4         42.3         41.9         40.7

Interest on ESOP                                 3.5          4.1          5.3          5.9          6.5          6.9          7.2

Portion of rents representative of
   interest factor                              20.0         18.0         21.4         28.7         26.1         19.2         15.4

                                          -----------  -----------  -----------  -----------  -----------  -----------  ----------- 
   Income as adjusted                     $    431.3   $    424.2   $    540.2   $    478.0   $    406.5   $    247.1   $    305.7
                                          ===========  ===========  ===========  ===========  ===========  ===========  =========== 

Fixed charges:

Interest on indebtedness                  $     32.9   $     41.2   $     55.5   $     46.4   $     42.3   $     41.9   $     40.7

Interest on ESOP                                 3.5          4.1          5.3          5.9          6.5          6.9          7.2

Portion of rents representative of
   interest factor                              20.0         18.0         21.4         28.7         26.1         19.2         15.4
                                          -----------  -----------  -----------  -----------  -----------  -----------  ----------- 

   Total fixed charges                    $     56.4   $     63.3   $     82.2   $     81.0   $     74.9   $     68.0   $     63.3
                                          ===========  ===========  ===========  ===========  ===========  ===========  =========== 

Ratio of earnings to fixed charges               7.6          6.7          6.6          5.9          5.4          3.6          4.8
                                          ===========  ===========  ===========  ===========  ===========  ===========  =========== 

Ratio of earnings to fixed charges (2)           8.3          8.4          8.4          7.6          7.4          5.3          6.2
                                          ===========  ===========  ===========  ===========  ===========  ===========  =========== 
<FN>
(1)   Income from continuing operations before provision for income taxes
      excludes the cumulative effect of changes in accounting principles.
(2)   The calculation of this ratio of earnings to fixed charges reflects the
      addition of the income from discontinued operations before the provision
      for income tax component for each period presented.
</FN>


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