Use of an ex situ, non-reversed, great saphenous vein as an arterial bypass graft for arterial ischaemia of the lower limb is described. After exposing the inflow and outflow arteries of the ischaemic limb, the great saphenous vein of the contralateral healthy limb is prepared. The proximal end of the vein is anastomosed with the inflow artery of the ischaemic limb after incising the valves of the proximal vein. The distal part of the vein is then divided, the remaining valves retrogradely transected and, after ensuring that all vein valves have been rendered incompetent, the distal end of the vein is anastomosed with the outflow artery of the ischaemic limb.