The use of varicose-ectatically altered veins in bypass surgery is unsatisfactory due to unfavorable flow dynamics and high closure rates. To date surgical repair possibilities to improve the flow profile of autologous vein bypasses have been limited. Using the patient's own veins to produce a biocompound graft, i.e. an ultraflexible hybrid prosthesis, is a simple method by which the surgeon can influence the profile and wall pressure of the bypass. The authors hope thus to improve the patency rate. When forming a biocompound graft, a vein is intraoperatively sheathed inside a fine ultraflexible metal mesh and the two joined with fibrin glue. The mesh hose is pulled over the entire length of the vein with the aid of an application set. Biocompound grafts were used as aorto-coronary bypasses in 9 patients (5 women, 4 men) in whom the possibility of using alternative bypasses did not exist. In 2 patients with femoro-popliteal bypass procedure the autologous varicose-ectatically altered vein was used as a biocompound-graft. Aorto-coronary bypasses: at the time of discharge from the hospital all biocompound bypasses were patent. No perioperative myocardial infarctions were observed. No wound infections occurred. Femoro-popliteal bypasses: at time of discharge from the hospital all biocompound bypasses were patent. The results prove the simplicity and reliability of this method in difficult surgical cases. The biocompound graft offers the surgeon the possibility of using varicose-ectatic veins if alternative bypasses are not available.