Femorofemoral bypass was chosen as a primary(n=71) and redo (n=7) procedures for 78 patients with unilateral iliac artery occlusive disease during the period of 4 and a half years at the Department of Surgery, Kyungpook National University Hospital. The patients were categorized into 3 groups according to the patency of the superficial femoral artery on the recipient-side leg and the performance of concomitant leg arterial bypass: Group I (n=34), patent superficial femoral artery (SFA); Group II (n=19), occluded SFA left untreated; Group III (n=25), occluded SFA treated with leg arterial bypass. Adjuvant procedures during the femorofemoral bypasses included 16 femoral endarterectomies, 5 donor-side iliofemoral interposition grafts, and 4 donor-side iliac balloon angioplasties. The primary cumulative patency rates for all femorofemoral bypasses at 1, 2, 3, and 4 years were 96.3%, 84.7%, 84.7%, and 74.2%, respectively calculated by the life table method. The primary patency rates were 90.0%, 62.9%, 62.9%, 62.9% in Group II and 95.7%, 89.5%, 89.5%, 89.5% in Group III at 1, 2, 3, and 4 years after bypass grafting. The statistical analysis with log rank test to compare the patency rates between Group II and III revealed no significant (p=0.2425) differences. In summary, femorofemoral bypass was a durable bypass procedure for the patients with unilateral iliac artery occlusion. Further follow-up is required to confirm the effects of concomitant leg arterial bypass to the patency of femorofemoral bypass.