This paper presents the results of conditioning studies in animals and in patients with epilepsy. In animals it was not possible to produce sensory evoked seizures by conditioning unless an epileptogenic lesion was produced. Patients with stroboscopic induced, startle, pattern and musicogenic epilepsy were treated by conditioning techniques. It was at first felt that the nature of this was an extinction process, but certain factors such as the need for reinforcement suggest that the therapy is actually a conditioning process. Changes in the electroencephalogram occur during this conditioning therapy as do changes in galvanic skin resistance.