A 77-year-old woman suffering from progressive dyspnea and chest pain for 2 1/2 years was admitted to hospital. There were no ECG changes at exercise test and a dobutamine stress echocardiography was normal. At catheterization, right-sided pressures were within normal limits. Coronary angiography revealed a congenital coronary fistula, 3-4 mm in diameter, from the left anterior descending artery to the proximal pulmonary artery. There was no significant rise in blood oxygen saturation in the pulmonary artery. Transcatheter coil embolization was performed in the distal part of the tortuous fistula. Flow ceased within minutes, demonstrating the feasibility and efficacy of this technique for treating large fistulas.