Lower gastrointestinal bleeding from a primary aortoduodenal fistula is unusual and usually fatal. Postoperative aortoduodenal fistula after biliary surgery is a very rare complication. We report hence a 69-year-old female patient who underwent a main bile duct resection with extended paraaortic lymphadenectomy for a cholangiocarcinoma. Acute melena with hemoglobin drop occurred on postoperative day 24. Initial CT-scan showed an aortic pseudoaneurysm with aortoduodenal fistula. An aortic endoprosthesis with endoscopic drainage of periaortic collections allowed successful treatment.