Indications and modalities of quality control in infrainguinal bypass surgery are reviewed and discussed. A concept and an armamentarium for its practical use are presented. The majority of graft occlusions occur during the first postoperative year. Most failures in the first month are due to technical errors. Many of these can be detected by intraoperative completion control, and immediately repaired. This contributes to improved graft patency rates. In the further course, myo-intimal hyperplasia accounts for most graft stenoses and occlusions. If stenoses are detected and dilated before occlusion occurs, long-term patency is but little impaired. Conversely, patency rates are clearly inferior in grafts following thrombectomy or thrombolysis. Therefore, identification of failing grafts and avoidance of failure are the objectives of surveillance. We have followed routinely a surveillance program since 1991. During surgery, grafts were controlled by completion angiography. Arterial pressures were measured and the ankle-brachial index calculated postoperatively and 1, 3, 6 and 12 months after surgery. In addition, a number of grafts were followed by duplex sonography. Data were stored in an electronic data base featuring several interactive functions. E.g., ankle-brachial and duplex-sonography indices were calculated and rated automatically according to current criteria. Secondary patency after 18 months was 86 per cent in suprageniculate femoro-popliteal bypass grafts, 84 per cent in infrageniculate and 65 per cent in crural (n = 19/23/27).