There is no consensus about the most appropriate management of the patient with intermittent claudication due to a superficial femoral artery occlusion. To evaluate the natural history of prosthetic above-knee femoropopliteal (AKFP) bypass, 200 operations for intermittent claudication were reviewed. One hundred AKFP bypasses were done with PTFE and 100 with dacron. In the 30 day postoperative period, four PTFE and three dacron grafts occluded without consequence and only one patient died. Analysis of results by the life-table method demonstrated statistically similar primary graft patency rates at five years (PTFE 65% SE +/- 6.5, dacron 57% +/- 6.2) and ten years (PTFE 31% +/- 18/9, dacron 32% +/- 13.2) (p greater than 0.10). Redo procedures (e.g., thrombectomy, angioplasty) were necessary on 21 grafts (12 PTFE, 9 dacron) and "secondary" patency rates at five years were 76% PTFE and 62% dacron; no grafts which required a redo procedure were patent at ten year follow-up. Major amputations during ten year follow-up were necessary in 16 (8%) patients; all amputations were in diabetic patients. Survival rates were 79% at five and 42% at ten years. An anticipated, the leading cause of death was cardiac related (25 patients); 28 (14%) patients underwent aortocoronary bypass during follow-up. A prosthetic AKFP bypass graft is a safe and durable operation which provides relief from the symptoms of intermittent claudication while allowing for the preservation of the saphenous vein for use later in the coronary or infrapopliteal circulations, should the need arise. These results indicate that the risk of amputation after AKFP is no greater than the natural history of untreated claudication; however, AKFP offers a significant improvement in life-style.