Abstract: The invention is directed to a system for determining gear ratio change in an automatic transmission in a vehicle having an accelerator pedal actuated by a driver of the vehicle. The system includes a first sensor for detecting the position (DK) of the accelerator pedal as a first variable and a second sensor for detecting the straight-line speed (V.sub.x) of the vehicle as a second variable. An adaptation variable (BZ) is determined in dependence upon at least one of the following: the instantaneous driving behavior of the driver, the environmental conditions to which the vehicle is subjected and the driving situation in which the vehicle is. A gear ratio change function includes a characteristic field for receiving the first and second variables (DK, V.sub.x) as first and second input variables (DK, V.sub.x), respectively. At least one of the first and second input variables (DK, V.sub.x) is changed in dependence upon the adaptation variable (BZ).