Exhibit 12(b)

                                         Aon Corporation and Consolidated Subsidiaries
                                           Combined With Unconsolidated Subsidiaries
                                  Computation of Ratio of Earnings to Combined Fixed Charges
                                                 and Preferred Stock Dividends


                                                     First Quarter
                                                    Ended March 31,                     Years Ended December 31,
                                                 -------------------- -----------------------------------------------------------
(millions except ratios)                             1998        1997       1997        1996        1995       1994        1993
                                                 ----------  ---------- ----------  ----------  ----------  ---------  ----------

 Income from continuing operations
                                                                                                        
    before provision for income taxes (1)          $ 237.8      $ 15.2    $ 541.6     $ 445.6     $ 458.0    $ 397.0     $ 331.6

 ADD BACK FIXED CHARGES:

    Interest on indebtedness                          20.1        14.6       69.5        44.7        55.5       46.4        42.3

    Interest on ESOP                                   0.7         1.0        3.5         4.3         5.3        5.9         6.5

    Portion of rents representative of
      interest factor                                 11.1        14.7       44.3        28.6        21.4       28.7        26.1

                                                 ----------  ---------- ----------  ----------  ----------  ---------  ----------
         INCOME AS ADJUSTED                        $ 269.7      $ 45.5    $ 658.9     $ 523.2     $ 540.2    $ 478.0     $ 406.5
                                                 ==========  ========== ==========  ==========  ==========  =========  ==========


 FIXED CHARGES AND PREFERRED STOCK DIVIDENDS:

    Interest on indebtedness                        $ 20.1      $ 14.6     $ 69.5      $ 44.7      $ 55.5     $ 46.4      $ 42.3

    Preferred stock dividends                         17.4        19.4       82.1        28.7        37.5       48.4        47.5

                                                 ----------  ---------- ----------  ----------  ----------  ---------  ----------
         Interest and dividends                       37.5        34.0      151.6        73.4        93.0       94.8        89.8

    Interest on ESOP                                   0.7         1.0        3.5         4.3         5.3        5.9         6.5

    Portion of rents representative of
       interest factor                                11.1        14.7       44.3        28.6        21.4       28.7        26.1

         TOTAL FIXED CHARGES AND PREFERRED
                                                 ----------  ---------- ----------  ----------  ----------  ---------  ----------
             STOCK DIVIDENDS                        $ 49.3      $ 49.7    $ 199.4     $ 106.3     $ 119.7    $ 129.4     $ 122.4
                                                 ==========  ========== ==========  ==========  ==========  =========  ==========

 RATIO OF EARNINGS TO COMBINED FIXED
   CHARGES AND PREFERRED STOCK DIVIDENDS (2)           5.5         0.9        3.3         4.9         4.5        3.7         3.3
                                                 ==========  ========== ==========  ==========  ==========  =========  ==========

 RATIO OF EARNINGS TO COMBINED FIXED
   CHARGES AND PREFERRED STOCK DIVIDENDS (3)                       3.8        4.2         5.8
                                                             ========== ==========  ==========
<FN>
(1)     Income from continuing  operations before provision for income taxes and
        minority  interest  includes  special  charges of $145  million in first
        quarter  ended March 31, 1997 and $172 million and $90.5  million in the
        years ended December 31, 1997 and 1996, respectively.

(2)     Included in total fixed  charges and preferred  stock  dividends for the
        first  quarter ended March 31, 1998 and 1997 are $16.4 million and $14.1
        million,  respectively,  and $64 million for the year ended December 31,
        1997  of  pretax  distributions  on the  8.205%  mandatorily  redeemable
        preferred capital securities which are classified as "minority interest"
        on the condensed consolidated statements of  operations.  The  ratio  of
        earnings  to  combined  fixed  charges  and  preferred  stock  dividends
        for  first  quarter  ended  March  31,  1997 is  less  than a one-to-one
        coverage indicating that earnings are inadequate to cover  fixed charges 
        by $4.2 million.

(3)     The calculation of this ratio of earnings to fixed charges  reflects the
        exclusion of special charges from the income from continuing  operations
        before  provision  for income taxes  component  for first  quarter ended
        March  31,  1997 and for the years  ended  December  31,  1997 and 1996,
        respectively.
</FN>