Antiarrhythmic agents may induce ventricular arrhythmias. Whereas amiodarone is a reported cause of ventricular fibrillation in children, there are no reported cases in infants. We observed two patients with atrial flutter and congestive heart failure who were treated with amiodarone. Both had anatomic heart defects and had failed conventional therapy. Ventricular fibrillation occurred 3 and 12 days after the initial dose. Q-T interval, electrolytes, digoxin level, and amiodarone level (one patient) were normal. Amiodarone may provoke life-threatening ventricular tachyarrhythmias during the convalescent period. Consideration should be given to monitoring in a hospital setting for at least 2 weeks following initiation of amiodarone therapy.