We describe the case of a man aged 42 who, five years before, had undergone aortocoronary bypass surgery using the internal mammary artery for the anterior and saphenous vein graft for the posterior descending arteries. Over the last one and a half years he had started to present angina pectoris as well as symptoms of vertebrobasilar insufficiency during exertion of the left upper extremity (recently during simple writing), whereas a full treadmill test was normal. Clinically, obstruction of the left subclavian artery was suspected with both coronary and subclavian steals. This suspicion was confirmed with tripler of the vessels of the aortic arch, coronary arteriography and carotid arteriography which demonstrated severe obstruction of the left subclavian artery at its origin and reversal of blood flow through the ipsilateral vertebral artery and the internal mammary artery graft. Angina subsided after balloon angioplasty of the subclavian artery. This combined steal, termed coronary subclavian syndrome, is rare (our case is probably the 20th reported), but an increase of its incidence is anticipated due to the widespread use of internal mammary artery grafts. The prevention and treatment of this syndrome are discussed.