To determine the importance of carotid artery disease in patients undergoing revascularization of the proximal subclavian artery for a subclavian steal syndrome, an 18-year experience of 55 patients was reviewed. Concomitant carotid artery disease (> 50% stenosis) was present in 35 patients (Group I: 63.6%). Twenty patients (Group II: 36.4%) had no evidence of hemodynamically significant carotid disease. Twenty-five patients in Group I (Group IA: 71.4%) were treated by endarterectomy (CEA) for all their carotid lesions while one or both carotid lesions were left untreated in 10 patients (Group IB: 28.6%). The actuarial 5-year freedom rate from neurological events was 87.2% in Group IA, 34.9% in Group IB (p < 0.001) and 100% in Group II (Group IB vs. II, p < 0.001; Group IA vs. Group II, p = ns). All untreated carotid lesions had a deleterious effect on the early and late functional results after surgical reconstruction of the subclavian artery. We conclude that the combined correction of subclavian and carotid lesions should be recommended in every case.