A control sytsem is disclosed for shifting gears in an automatic shift gear box (3) by using fuzzy logic methods. Vehicle parameters form input variables (8) that are continuously detected by appropriate means (9). These input variables are further processed in downstream functional blocks (11, 12, 13, 14, 15, 16 and 17). Gear shifting points that ensure an economical driving are determined in the functional block (11) according to fuzzy logic methods. Besides a set of basic fuzzy logic generating rules, additional rules are used to improve driving. For that purpose, the input quantity "desired performance" is taken into consideration in both sets of rules. The desired performance may be a desired acceleration or a desired deceleration. In order to form a closed regulation circuit, the fictitious quantity "desired performance" and the quantity "driving manner" are converted into physical quantities.