Since Krause first described coronary arteriovenous fistula in 1865, there have been nearly 300 additional patients with this malformation reported in the literature. Increasing numbers of patients with this anomaly are being recognized each year resulting from the widespread use of cardiac catheterization and selective coronary arteriography in the evaluation of a variety of cardiac problems. A 9 month old male was admitted with the chief complaint of cardiac murmur and frequent URI and diagnosed as coronary A-V fistula at the distal portion of left anterior descending coronary artery to the apex of the right ventricle by cardiac catheterization and aortography. On the operative field, the left anterior descending coronary was markedly dilated about 1.5 cm in diameter from the aorta to the apex of the heart. The fistula opening was closed with 5-0 Prolene continuously under cardiopulmonary bypass and moderate hypothermia[28*C]. Postoperative course was uneventful and the patient was discharged without problem.