Some surgeons have advocated using polytetrafluoroethylene (PTFE) as the graft material of choice for femoropopliteal arterial bypass so that the saphenous vein could be preserved for future cardiovascular surgery. We have examined our results to see if this approach could be justified in our patient population. PTFE was used for 101 femoropopliteal reconstructions in 96 patients (56 male and 40 female). Thirty-eight (40%) complained of debilitating claudication and 58 (60%) had limb-threatening ischaemia. There were 83 primary PTFE femoropopliteal reconstructions and 18 repetitive procedures after failure of an earlier ipsilateral bypass. Twenty-nine of the 101 PTFE grafts were anastomosed distally to the popliteal artery above knee and the remaining 72 below knee. At 5 years, the cumulative patency for all grafts was only 11%. The 4 year cumulative patency was better for claudicants (40%) than for those with threatened limb loss (11%) but two of the 38 claudicants required amputation when their grafts failed. Patency rates were not significantly affected by the site of the distal anastomosis or by a previous failed ipsilateral femoropopliteal bypass. Worthwhile limb salvage was achieved only by frequent re-operation. Our results with PTFE are not good enough to use it in preference to an adequate saphenous vein for femoropopliteal bypass.