Controversy continues regarding the best arterial substitute for femoropopliteal reconstruction if an adequate length of autogenous saphenous vein is not available. To evaluate the role of composite grafts as an alternate vascular conduit, 39 femoropopliteal composite grafts were analyzed and compared with a similar group of 79 below-knee prosthetic reconstructions. The 5-yr cumulative patency rates for composite and prosthetic reconstructions to the distal popliteal artery were not statistically different (38 .+-. 9% and 31 .+-. 8%, respectively). The amount of vein relative to prosthesis did not appear to influence late patency. Both alternate reconstructive methods were significantly inferior to the 73 .+-. 3% 5-yr patency rate of autogenous vein bypass grafts. The use of composite grafts for primary femoropopliteal reconstruction was abandoned, since currently available prosthetic grafts appear to have similar long-term function.