The effects of coronary bypass grafting on ventricular tachycardia induced by treadmill stress testing (TST) were analyzed in nine patients by repeating the test an average of 5 months after operation. Preoperatively, eight patients experienced pain and all had ischemic ST-segment depression during exercise. Six patients had a single episode and two patients had multiple episodes of ventricular tachycardia; in one patient ventricular tachycardia degenerated into ventricular flutter necessitating direct-current cardioversion. Postoperatively, time of exercise and double product were significantly higher during TST. Electrocardiographic ischemic changes were present in only two patients and ventricular tachycardia was not observed. All patients are alive and average of 24 months after the operation, and eight of them are asymptomatic. In conclusion, among patients with coronary artery disease who have exercise-induced ventricular arrhythmias, myocardial revascularization is associated with improvement of exercise capacity and suppression of arrhythmias.