Coronary artery aneurysm and ectasia, unusual angiographic findings, are considered as variant of atherosclerotic coronary artery disease. A 49-year-old man whose right coronary artery ectasia had progressed to large aneurysm, accompanied by advanced obstructive coronary artery disease, 6 years after the initial coronary artery bypass grafting. It was treated with ligation of aneurysm and distal bypass grafting under cardiopulmonary bypass. Fragile fresh clot was formed within the aneurysm irrespective of coumadin therapy as a standard regimen for the coronary artery ectasias. We will discuss the surgical management for the dilated coronary artery with significant coronary stenosis.