A patient had undergone resection of an abdominal aortic aneurysm 12 years earlier in which a synthetic aortic graft was used. An aortoduodenal fistula occurred at the proximal aortic anastomosis where a false aneurysm had developed, and massive gastrointestinal bleeding resulted. In the absence of infection, the existing grafts were salvaged by division of the fistula, resection of the false aneurysm, and replacement with a new synthetic graft. The patient has had an uncomplicated course and remains well six months postoperatively. A high index of suspicion for this problem is urged for any patient with gastrointestinal bleeding who has a synthetic aortic graft.