It is generally acknowledged that congenital coronary artery fistula is an abnormal communication of the coronary artery with the right ventricle, right atrium,left atrium and left ventricle. In young people the symptoms are unusual , but significant symptoms and complications appear among the older age group such as congestive heart failure, subacute bacterial endocarditis, coronary steal syndrome, aneurysm formation, rupture, and pulmonary hypertension. Therefore, early surgical treatment is recommended. We experienced a case of coronary arteriovenous fistula that was involving the circumflex branch of the left coronary artery with the right ventricle. It was 10mm in diameter with multiple vegetation. We repaired the fistula under extracoporeal circulation. The patient was discharged in a healthy condition twelve days after operation .