An 18-year-old asymptomatic male was found to have a high-flow systemic arterial to pulmonary arterial fistula fed by dilated lower intercostal arteries draining via pulmonary artery toward the left main pulmonary trunk. Transcatheter Guglielmi Detachable Coil (GDC. Target Ther, Fremont, Calif.) embolization was performed. Transcatheter embolization is a reasonable and less invasive mode in the treatment of systemic artery to pulmonary artery fistula, and GDC offers more precise coil placement over other conventional coils