<PAGE>   1
                                                                      Exhibit 12


AETNA INC.

RESTATED
COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES AND RATIO OF EARNINGS
TO COMBINED FIXED CHARGES AND PREFERRED STOCK DIVIDENDS

<TABLE>
<CAPTION>
                                                Six Months Ended                                 Years Ended
                                                    June 30,                                     December 31,
                                              -------------------       ----------------------------------------------------------
(Millions)                                      1999        1998           1998          1997        1996       1995         1994
----------                                    -------     -------       ---------     ---------    -------    -------      -------
<S>                                           <C>         <C>             <C>           <C>        <C>        <C>          <C>
Pretax income from
    continuing operations                     $ 641.6     $ 682.0       $ 1,408.3     $ 1,511.2    $ 338.7    $ 726.2      $ 627.5

Add back fixed charges                          189.4       165.4           358.5         321.9      245.1      187.0        170.8
Minority interest                                10.6         0.9            10.7          14.7       16.4       16.1         11.4
                                              -------     -------       ---------     ---------    -------    -------      -------

    Income as adjusted                        $ 841.6     $ 848.3       $ 1,777.5     $ 1,847.8    $ 600.2    $ 929.3      $ 809.7
                                              =======     =======       =========     =========    =======    =======      =======

Fixed charges:
    Interest on indebtedness (1)              $ 128.7     $ 113.4         $ 250.9       $ 235.8    $ 168.3    $ 115.9       $ 98.6
    Portion of rents representative
        of interest factor                       60.7        52.0           107.6          86.1       76.8       71.1         72.2
                                              -------     -------       ---------     ---------    -------    -------      -------

    Total fixed charges                       $ 189.4     $ 165.4         $ 358.5       $ 321.9    $ 245.1    $ 187.0      $ 170.8
                                              =======     =======       =========     =========    =======    =======      =======

  Preferred stock dividend
    requirements                                 45.7        45.7            92.2          92.4       41.1          -            -
                                              -------     -------       ---------     ---------    -------    -------      -------
  Total combined fixed charges
    and preferred stock dividend
      requirements                            $ 235.1     $ 211.1         $ 450.7       $ 414.3    $ 286.2    $ 187.0      $ 170.8
                                              =======     =======       =========     =========    =======    =======      =======

  Ratio of earnings to fixed
      charges                                    4.44        5.13            4.96          5.74       2.45       4.97         4.74
                                              =======     =======       =========     =========    =======    =======      =======

  Ratio of earnings to combined
    fixed charges and preferred
    stock dividends                              3.58        4.02            3.94          4.46       2.10       4.97         4.74
                                              =======     =======       =========     =========    =======    =======      =======
</TABLE>


(1)      Includes the dividends paid to preferred shareholders of a subsidiary.
         (Refer to Note 16 of Notes to Consolidated Financial Statements in the
         Company's 1998 Form 10-K/A.)


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                                                          Exhibit 12 (Continued)
AETNA SERVICES, INC. (1)

COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES AND RATIO OF EARNINGS TO
COMBINED FIXED CHARGES AND PREFERRED STOCK DIVIDENDS


<TABLE>
<CAPTION>
                                                         Six Months Ended                             Years Ended
                                                             June 30,                                 December 31,
                                                      -----------------------           ----------------------------------------
(Millions)                                              1999            1998               1998           1997             1996
----------                                            -------         -------           ---------      ---------         -------
<S>                                                   <C>             <C>               <C>            <C>               <C>
Pretax income from continuing operations              $ 473.0         $ 635.1           $ 1,162.7      $ 1,505.2         $ 335.0

Add back fixed charges                                  187.9           163.3               354.3          318.1           243.8
Minority interest                                         9.7              .4                10.8           15.7            16.4
                                                      -------         -------           ---------      ---------         -------

   Income as adjusted                                 $ 670.6         $ 798.8           $ 1,527.8      $ 1,839.0         $ 595.2
                                                      =======         =======             =======        =======         =======

Fixed charges:
   Interest on indebtedness (2)                       $ 128.7         $ 113.4             $ 250.9        $ 234.0         $ 168.3
   Portion of rents representative
       of interest factor                                59.2            49.9               103.4           84.1            75.5
                                                      -------         -------           ---------      ---------         -------

    Total fixed charges                               $ 187.9         $ 163.3             $ 354.3        $ 318.1         $ 243.8
                                                      =======         =======             =======        =======         =======

Preferred stock dividend requirements                       -               -                   -              -               -
                                                      -------         -------           ---------      ---------         -------

Total combined fixed charges and preferred
    stock dividend requirements                       $ 187.9         $ 163.3             $ 354.3        $ 318.1         $ 243.8
                                                      =======         =======             =======        =======         =======

Ratio of earnings to fixed charges                       3.57            4.89                4.31           5.78            2.44
                                                      =======         =======             =======        =======         =======

Ratio of earnings to combined fixed charges
    and preferred stock dividends                        3.57            4.89                4.31           5.78            2.44
                                                      =======         =======             =======        =======         =======
</TABLE>

(1)      Aetna Inc. has fully and unconditionally guaranteed the payment of all
         principal, premium, if any, and interest on all outstanding debt
         securities of Aetna Services, Inc. (Refer to Note 15 of Notes to
         Financial Statements in the Company's 1998 Form 10-K/A.)

(2)      Includes the dividends paid to preferred shareholders of a subsidiary.
         (Refer to Note 16 of Notes to Consolidated Financial Statements in the
         Company's 1998 Form 10-K/A.)


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