Between January 1970 and April 1989, 20 patients underwent operation for secondary aortoduodenal fistulas. When the preoperative diagnosis was certain and emergency control of bleeding not required, initial axillofemoral bypass was performed before ablation of the infected aortic prosthetic graft during the same operation. When diagnosis was uncertain or severity of bleeding required emergency laparotomy, the therapeutic plan varied over time. Until 1980, we performed either a direct repair (three cases) or the ablation of the aortic graft followed by secondary axillofemoral bypass (four cases). After 1980, the order of procedures was 1) control of bleeding whenever necessary, 2) axillofemoral bypass, and 3) ablation of the aortic graft. Postoperative mortality was two of 13 in patients undergoing initial axillofemoral bypass, compared with six of seven patients undergoing direct surgery or initial ablation of the aortic graft. Of the 12 patients surviving the postoperative period, three died of aortic stump hemorrhage, four, 12, and 14 months after operation. Two patients had a new aortic graft inserted. Repeat replacement of the abdominal aorta graft was performed in one case and ascending thoracic aortobifemoral bypass in the other because of secondary thrombosis of the axillofemoral bypass. We conclude that initial axillofemoral bypass before dealing with the aortic graft improves the immediate prognosis in operations for secondary aortoduodenal fistulas. This procedure does not, however, preclude the possibility of aortic stump infection which can lead to recurrent aortoduodenal fistula. The risk of infection or secondary occlusion of axillofemoral bypass is minimal. Secondary prosthetic replacement is not systematically necessary.