Polytetrafluoroethylene (PTFE) bypasses were used in a series of arterial reconstructions to the popliteal artery (45) and to arteries below that level (11). These were performed in high-risk situations in patients who lacked a suitable saphenous vein. Vein bypasses were performed in a comparable series of high-risk situations in patients having a suitable autologous saphenous vein (45 to the level of the popliteal artery and 11 to an artery below that level). PTFE patency rates at 4-14 months were 43 to 45 (96%) for the femoro-popliteal reconstructions (with a limb salvage rate of 39 to 45 or 87%) and 5 of 11 (45%) for the distal bypasses. Saphenous vein bypass patency rates at 8-14 months were 39 of 45 (87%) for the femoropopliteal reconstructions (with a limb salvage rate of 36 of 45 or 80%) and 5 of 11 (45%) for the distal bypasses. These results justify continued use of PTFE grafts in patients without saphenous veins who require lower extremity arterial reconstructions for limb salvage. The exact place of PTFE grafts in arterial reconstructive surgery of the lower extremity definition based on longer periods of observation.