Postoperative lower extremity lymphangiograms and phlebograms were performed in 14 patients following femoropopliteal autogenous vein bypass in an effort to determine the cause of leg edema frequently seen following this procedure. Similar studies were performed in three patients following varicose vein removal, and in three patients following aortofemoral prosthetic grafting. Postoperative leg edema occurred in nine of 14 patients following femoropopliteal bypass. The severity and duration of postoperative edema correlated in every patient with the magnitude of disruption of the inguinal lymphatics. Minor operative modifications to minimize inguinal lymphatic damage during femoropopliteal bypass decreased the incidence and severity of postoperative edema.