Four cases of peroneal palsy have been reported. One occurred 2 months after the cessation of ECT so that the role of ECT in its etiology is difficult to evaluate. Another occurred in a diabetic and the role of the diabetes has to be considered with the ECT. The other 2 cases appear to be free of extraneous factors.All of these patients were in poor nutrition, were inactive and were in the age group where arteriosclerosis is often seen. These factors have been indicated as playing a role in the development of peroneal palsies. However, the role of electroconvulsive treatments in the etiology of these peroneal palsies cannot be neglected and should be considered as a complication of ECT in older patients who have been depressed, immobile, and in poor nutrition.