Tibiofemoral bypass operations were performed in 106 patients with stage III or IV lower limb arterial insufficiency. Follow-up has been for from 1 to 14 years. Results of arteriography, the operative technique used and the choice of bypass material (which should be the internal saphenous vein for preference) are discussed. Permeability was still present in 73% of cases after one year, 66% after 3 years, 62% after 5 years and 57% after 10 years. The incidence of amputation was less than that of obstructed by-passes. Treatment failures are analyzed as a function of the distal network, i.e. the receiving artery, and as a function of distal lesions and material employed. Confirmation was obtained of the superiority of autologous venous bypass material, taking into account the negative selection in cases with a prosthetic shunt. A lower limb with arterial insufficiency and menaced with amputation can often be saved, even when arterial lesions extend beyond the popliteal segment.