The choice of the prosthetic material in arterial surgery of patients with rest pain and/or impending gangrene of the lower limbs still presents several problems. The poor run-off, the small caliber of the distal vessels, the crossing of the joint areas and the length of the bypass may lead to early occlusion of the prosthesis. This experience is based on 268 femoro-distal (214 femoro-popliteal below the knee and 54 femoro-tibial) and on 121 axillo-femoral/popliteal bypasses (89 axillo-femoral, 28 axillo-bifemoral and 4 axillo-popliteal). In the 389 surgical procedures we have employed the autologous saphenous vein in 208 cases, Polytetrafluoroethylene (PTFE) straight or tapered in 66, PTFE external supported (EXS) in 33, Dacron in 12, homologous saphenous vein in 7 and PTFE EXS Thin Wall in 5. In 58 cases a composite graft (autologous saphenous vein plus synthetic prosthesis) was used. The cumulative long term (12-96 months) patency is 75.96% for autologous saphenous vein bypass, 62.12% for PTFE, 75.75% for PTFE EXS, 41.66% for Dacron, 42.85% for homologous saphenous vein and 84.48% for the composite graft. All the PTFE EXS Thin Wall grafts are still patent (12 months).(ABSTRACT TRUNCATED AT 250 WORDS)