We describe surgical treatment of a coronary artery fistula (CAF) in a neonate. A 5-day-old male neonate was diagnosed with CAF at another hospital and was transferred to our hospital. Transthoracic echocardiography revealed a right coronary artery-to-right ventricle (RV) fistula. Emergency surgery was performed to treat progressive congestive heart failure due to a significant left-to-right shunt through the large CAF. Intraoperatively, we confirmed that the large CAF drained into the inlet of the RV through multiple openings. Intracardiac CAF closure was performed with a bovine pericardial patch. The neonate showed an uneventful postoperative recovery, and postoperative echocardiography revealed a trivial residual shunt with good left ventricular function without increased pulmonary artery pressure.