<PAGE>   1
                                                                    EXHIBIT 12-1


              MICHIGAN CONSOLIDATED GAS COMPANY AND SUBSIDIARIES
              COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES
                             (THOUSANDS OF DOLLARS)



<TABLE>
<CAPTION>

                                                             Twelve Months Ended  Twelve Months Ended  Twelve Months Ended 
                                                             -------------------  -------------------  ------------------- 
                                                              September 30, 1997   December 31, 1996    December 31, 1995  
                                                             -------------------  -------------------  ------------------- 
                                          
<S>                                                          <C>                  <C>                  <C>                 
EARNINGS AS DEFINED (1)                   
Net Income ..........................................               $119,328           $122,239             $112,727     
Fixed charges .......................................                 57,789             53,831               45,637     
                                                                    --------           --------             --------     
 Earnings as defined ................................               $177,117           $176,070             $158,364     
                                                                    ========           ========             ========     
                                          
FIXED CHARGES AS DEFINED (1)              
Interest on long-term debt ..........................               $ 46,463           $ 43,163             $ 35,820     
Interest on other borrowed funds ....................                  8,802              8,012                7,053     
Amortization of debt discounts, premium   
 and expense ........................................                  1,059              1,081                  996     
Interest implicit in rentals (2) ....................                  1,465              1,575                1,768     
                                                                    --------           --------             --------     
 Fixed charges as defined ...........................               $ 57,789           $ 53,831             $ 45,637     
                                                                    ========           ========             ========     
         
Ratio of Earnings to Fixed Charges ..................                   3.07               3.27                 3.47     
                                                                    ========           ========             ========     
</TABLE> 
                                          


Notes:
(1)  Earnings and fixed charges are defined and computed in accordance with
     Item 503 of Regulation S-K.
(2)  This amount is estimated to be a reasonable approximation of the
     interest portion of rentals.

MichCon is a guarantor of certain other debt.  Fixed charges related to such
debt are deemed to be immaterial and therefore have
been excluded from the above ratios.