Verapamil is a useful drug for treating supraventricular tachycardia; however, severe side effects occasionally have been reported in infants. We describe here our experience with the use of a 10 percent solution of intravenous calcium gluconate prior to the use of verapamil in infants with paroxysmal supraventricular tachycardia. In all the attacks verapamil converted the supraventricular tachycardia to sinus rhythm. We feel that calcium gluconate injected previous to verapamil can avoid the negative inotropic effects without interfering with the antiarrhythmic properties of verapamil.