A 15-year-old girl underwent successful radiofrequency ablation of an accessory pathway. Following ablation, a new III/VI diastolic murmur was noted. Echocardiography revealed a perforated aortic leaflet, with a small amount of adherent valvular tissue and trivial aortic insufficiency by color Doppler. The patient remains asymptomatic. We are not aware of any similar complication from electrophysiological study, catheter ablation, coronary angiography, or percutaneous transluminal coronary angioplasty. We speculate that the current state of catheter technology contributed significantly to this complication. This case illustrates the need for using care in crossing the valve, continued advances in catheter technology to reduce the incidence of complications, and careful physical examination prior to and following attempts at ablation.