Secondary aortoenteric fistula (SAF) is now recognized as an uncommon but exceedingly important complication of abdominal aortic reconstruction. The complication often occurs months to years after the original surgery. The main clinical manifestation of the disease is always upper gastrointestinal bleeding. Treatment of the disease is early surgical intervention. The mortality is high if no prompt operation. We present a case of secondary aortoduodenal fistula (SADF) found 20 days after aortic reconstructive surgery, with the clinical presentation of upper gastrointestinal bleeding. Even immediate exploratory laparotomy was performed, the patient died 48 hrs after the surgical management. Because of the increasing number of elective aortic aneurysm repairs in the aging population, it is likely that more patients with SAF will present to the clinical physicians in the future. So, a high index of suspicion is necessary for prompt diagnosis and treatment of this actually life-threatening event.