In a series of 245 vein grafts, results of 163 from the common femoral artery were compared with 82 from the proximal superficial femoral artery. Groups were comparable for risk factors, except that significantly more of the superficial femoral artery group were anastomosed to a single calf vessel (P less than 0.02). Early technical failure was similar in both groups (14 per cent common femoral artery, 12 per cent superficial femoral artery, P = n.s.). Cumulative life table patency rates at 1 and 3 years were 77 per cent and 72 per cent in common femoral artery grafts, and 80 per cent and 70 per cent in superficial femoral artery grafts (P = n.s.). Analysis of 92 veins in situ (65 common femoral artery and 27 superficial femoral artery) showed 1-year patency rates of 75 per cent in common femoral artery grafts and 79 per cent in superficial femoral artery grafts (P = n.s.). These results suggest that the proximal superficial femoral artery is a safe inflow site for distal bypasses.