A 67-year-old man presented complaining of unstable angina. Coronary angiography revealed 50% stenosis of the left main trunk of the left coronary artery and a coronary artery aneurysm in the left anterior descending artery (LAD) #6. Furthermore, significant stenosis was noted in the peripheral LAD #7 and #9. The patient had hepatitis C, probably due to an earlier transfusion, and was suffering from liver cirrhosis (Child-Pugh classification grade A) and advanced thrombocytopenia. We anastomosed the saphenous vein graft (SVG) to the LAD and diagonal branch by off-pump coronary artery bypass grafting; we did not treat the aneurysm. There were no postoperative complications and the patient's progress was good. On postoperative coronary angiography, the aneurysm was occluded and the patency of the SVG was satisfactory.