Surgical repair of left ventricular diverticulum usually is not required in infancy even though it combines with other anomalies. In addition to prevention of rupture of the diverticulum and thrombus formation, treatment of combined ventricular tachycardia is thought to be an indication for resection of the diverticulum. We describe a successful repair performed by excising the isolated left ventricular diverticulum under cardiopulmonary bypass in a 9-day-old infant. The combined ventricular bigeminy has disappeared 9 months after the operation.