A case of coronary subclavian steal following coronary artery bypass grafting (CABG) using the internal thoracic artery (ITA) in the presence of the stenosis of the left subclavian artery (SCA) is reported. The patient was a 70-year-old woman who developed recurrent angina about one year and three months after CABG with an ITA to LAD, and then underwent postoperative coronary arteriography. Angiograms revealed retrograde flow through the ITA to the left SCA and severe stenosis of the origin of the left SCA. Restoration of antegrade flow througn a left ITA graft to the coronary artery was achieved by balloon angioplasty to the stenosis of SCA. This procedure resulted in resolution of symptoms. The coronary subclavian steal is an infrequent, but very important complication after CABG with an ITA, and should be kept in mind in this mode of CABG.