Significant initial and long term salvage can be achieved with popliteal arterial bypasses using either autogenous saphenous vein or woven Dacron. Long term experience with these materials show that they should serve as standards for the comparison of newer materials. Autogenous vein femoropopliteal bypasses result in higher average initial and long term graft function than do Dacron femoropopliteal grafts. However, depending upon the anatomic area, the superiority of vein grafts is not always apparent. Arterial prosthetic materials must be carefully evaluated in regard to initial and long term function. Before general use of recently developed arterial substitutes is recommended, their function must be shown to be superior to that of well known arterial prostheses.