This article presents a personal computer-based control system for an electrical stimulator using fuzzy logic. The input signal comes from a goniometer and the output is the stimulation level to be applied in the muscle of the patient. By this way, that control system is made for the therapist that just specify the desired joint's angle. The movement that the patient will execute can be mimicked from a person with normal movements, storing his or her joint's angles during the execution of some task, and later reproducing it in the person without the voluntary movements. Such movements will be more proper of a human than a planned execution by a computational system, which the movement is structuralized by means of vectors, angles and times placed of supposed form.