Exhibit 12 MICHIGAN BELL TELEPHONE COMPANY COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES (Dollars in thousands) Nine Months Nine Months Ended Ended September 30, September 30, 1994 1993 1. Earnings (a) Income before interest expense and income taxes. $283,235 $426,546 (b) Single Business Tax 22,050 20,610 (c) Portion of rental expense representative of the interest factor (1) (2) 8,263 10,154 Total 1.(a) through (c) $313,548 $457,310 2. Fixed Charges (a) Total interest deductions $73,380 $79,813 (c) Portion of rental expense representative of the interest factor (1) (2) 8,263 10,154 Total 2.(a) and (b) $81,643 $89,967 3. Ratio (1. divided by 2.) (3) 3.84 5.08 (1) The Company considers 1/3 of rental expense to be the amount representing return on capital and therefore it must be included in fixed charges. (2) Earnings are income before income taxes and fixed charges. Since the Single Business Tax and rental expense have already been deducted, the Tax and the 1/3 portion of rental expense considered to be fixed charges are added back. (3) The results for the first nine months of 1994 reflect $194.7 in pre-tax changes for work force restructuring (see MD&A discussion of these charges). Such charges will be funded primarily from the Ameritech Pension Plan.