Abdominal aortic aneurysms (AAAs) can cause aortoenteric fistulae (AEF). AEF can either be primary, arising from the aneurysm or other diseases, causing the aorta to erode into the bowel, or secondary, from previous aortic grafting. Primary aortoduodenal fistula (ADF) is a rare clinical entity that usually presents with gastrointestinal bleeding that can be occult, intermittent, or massive. We report a 71-year-old woman with acute onset of abdominal pain and massive hematemesis. Esophagogastroduodenal endoscopy (EGD) and arteriography were nondiagnostic. The patient's condition became unstable, and she was brought emergently to the operating room where the diagnosis of an ADF was made. The ADF and AAA were surgically repaired, and the patient recovered without complications. This case represents an example of a rare complication of AAA with the unusual presentation of multiple aortic aneurysms. We will address the pathophysiology, diagnostic evaluation, and management of AEF.