We reported an operative case of bilateral coronary arteries to pulmonary artery fistula with giant saccular aneurysm. This 68 year-old female was admitted for evaluation of chest oppression and heart murmur. On coronary angiography, the diagnosis was made as a coronary artery fistula originating from right coronary artery and left anterior descending artery, and draining into the main pulmonary artery. The operation was indicated by giant saccular aneurysm, high shunt ratio, and positive finding of ischemic change on exercise electrocardiogram. The closure of coronary fistula and aneurysmorrhaphy were performed under cardiopulmonary bypass. The aneurysm was 25×30mm diamater, and not found arteriosclerotic change in operative finding. The fistula was completely disappeared by postopertive coronary angiography. We concluded that curative operation for coronary artery fistula with giant aneurysm can be done with minimal risk under cardiopulmonary bypass.