Primary aortoenteric fistula is a direct communication between the aorta and intestinal lumen and it represents a rare but potentially lethal complication of an abdominal aortic aneurysm. However, it may occur less frequently in a naive non-aneurysmatic aorta. Diagnosis is often difficult and delayed in most cases, unless there is a high level of clinical awareness. Urgent surgery is still the recommended treatment. We describe the case of primary aortoenteric fistula of a saccular aneurysm. A 55-year-old woman was referred to our center with hematemesis, melena, and severe anemia who was dignosed previously with unknown saccular abdominal aneurysm.