Revascularisation of the lower limbs with vein graft is frequent. Femoro-popliteal infrainguinal bypass have good permeability rates at five years. The weak point of autogenous vein bypass grafting is vein graft stenosis, which develops particularly in the first post-operative year. Stenoses are mostly in relation with myo-intimal hyperplasia and are often located at anastomoses. Serial arteriography and echographic studies have shown that the development of intrinsic graft stenosis is found in 20 to 30% of vein conduits in the lower extremity. On the basis of an abundance of clinical data, Duplex ultrasound surveillance of infrainguinal vein graft to detect and repair such lesions before graft occlusion is widely accepted and has shown in many retrospective studies to have a positive influence on lifetime of venous grafts. Critical stenosis (peak systolic velocity (PSV) > 300 cm/s and velocity ration (VR) > 4) should undergo surgical revision as it heralds occlusion of the vein graft in short delays. Intermediate stenosis (peak systolic velocity (PSV) 200-300 cm/s and velocity ratio (VR) 2-4 should be accurately followed as 50 to 70% progress to critical stenosis. Use of echo-doppler monitoring is supported by one randomised study which showed superiority of ultrasound surveillance over clinical surveillance, and by a well described relation between graft thrombosis and an increased amputation rate. In contrast, Duplex ultrasound surveillance for prosthetic grafts is not widely accepted primarily because of the occurrence of rare intrinsic lesions in prosthetic grafts, compared to in vein grafts. Vascular doctors are increasingly concerned with the costs of surveillance program and of surgical interventions. Recent economic appraisal have shown that cost associated with graft maintenance is significant, particularly in the first-year and demands consideration. However revision of a duplex-identified stenosis seems to be less costly than revision after graft thrombosis. Costs of limb amputation and the following expense of postamputation rehabilitation are very high and justify limb-salvage-related expense. The results of an ongoing randomised controlled trial (the Vein Graft Trial) comparing duplex ultrasound surveillance against clinical surveillance only will certainly bring more data on the benefits of echographic surveillance.