The results of 240 femoro-distal bypass operations for critical ischemia have been reviewed. Autologous saphenous vein was the graft material in 112 cases (46.7%) and prosthetic grafts were used in the other 128 cases (53.3%). A distal arteriovenous shunt (AVS) was employed as an adjunct to 72 grafts (30%). The cumulative patency rate at 4 years was 53% for all of the grafts together and the cumulative limb salvage rate was 70%. When autologous saphenous vein was available the actual patency rate at one year after operation was 70% for popliteal grafts and 53% for tibial grafts. In the case of prosthetic grafts the equivalent patency rates were 51% and 35%. In view of the poor success rate of prosthetic grafts anastomosed to distal tibial vessels these procedures are of doubtful value in routine clinical practice.