Eighteen patients with recurrent ventricular fibrillation complicating acute myocardial infarction were treated with bretylium tosylate. All except one patient had been given therapeutic doses of lidocaine and some, in addition, had received other antiarrhythmic agents before bretylium. Bretylium therapy was initiated with intravenous administration of 5 mg/kg body weight and was usually maintained by administering the same dose every 6 to 8 hours by intramuscular route. Ten patients recovered while eight died. Only two of the survivors exhibited heart failure and none of them was in shock, while cardiogenic shock dominated the course of patients with fatal outcome. Postural hypotension invariably occurred but without any clinical deterioration of cardiac function. It is concluded that often bretylium tosylate is an effective therapeutic agent in suppression of recurrent or resistant ventricular fibrillation.