A 63-year-old man presented with subclavian steal syndrome associated with left internal mammary artery (IMA) bypass graft to a coronary artery. He was admitted with a history of oppressive sensation in the chest, dizziness, and light headedness on exertion for 2 weeks in March 2002. He had undergone myocardial revascularization consisting of a left IMA-to-left anterior descending coronary artery graft in April 1988. His blood pressure was 140/70 mmHg in the right arm and 80/64 mmHg in the left arm. Aortic arch arteriography revealed complete occlusion of the left subclavian artery proximal to the left IMA takeoff and subclavian steal with anterograde flow of the left IMA. Percutaneous angioplasty and stent placement with protection of the left IMA bypass graft using a balloon catheter was successfully performed without complication by cerebral or myocardial ischemia. Complete recanalization of the occluded left subclavian artery and anterograde flow of the left vertebral artery were achieved. His symptoms disappeared and blood pressure in the left arm recovered. This variant of coronary subclavian steal might require protection of the left IMA during angioplasty and stent placement.