In an eight year-period from 1988 to 1995 653 femoropopliteal and femorocrural bypasses were performed. 347 above-knee reconstructions 206 below-knee reconstructions and at last 100 femorocrural bypasses were analysed. The cumulative patency rate after a follow up of three years for above-knee vein bypasses was 90%, patency rate for PTFE grafts in the same period was 52%, for ovine collagen grafts 56%. For below-knee bypasses with autologous saphenous vein a function rate of 76% could be observed in the same period, the rate of PTFE grafts in this position was only 30%. In this position 3-year patency rates of 50% were achieved with ovine collagen grafts. This difference was statistically significant. Three years cumulative patency rate for femorocrural reconstructions with greater saphenous vein was 72%, the function rate for PTFE in this position was below 30% after a follow up of one year, with ovine grafts below 40%. Graft infection, aneurysm formation and postoperative mortality were low in all groups. Our data demonstrate, that patency rates of autologous vein bypasses could not be achieved with PTFE or ovine collagen prosthesis in any femoropopliteal the femorocrural position. We therefore cannot confirm the recommendation to use alloplastic grafts as primary choice for above knee bypasses to spare the saphenous vein.