A 70-year-old lady presented with recurrent gastrointestinal bleeding and septicemia caused by multiple enteric pathogens. She was diagnosed to have primary aorto-enteric fistula (PAEF) complicating abdominal aortic aneurysm. Endovascular aneurysm repair was carried out that arrested gastrointestinal bleeding, but despite prolonged antibiotic therapy the patient died a month later of probable sepsis. PAEF refers to abnormal communication between the aorta and the intestine resulting from disease at either site; this rare condition should be suspected in patients with abdominal aortic aneurysm who present with unexplained life-threatening gastrointestinal bleeding. Computerized tomography is the most sensitive investigation. Presence of ectopic gas adjacent to or within the aorta and of contrast within the gastrointestinal tract is the pathognomonic finding. Definitive treatment consists of surgical intervention, but it is associated with high risk in the acute setting. Endovascular therapy using stent-grafts is safe and effective in arresting gastrointestinal bleeding. However, it is frequently associated with recurrent sepsis even with continued antibiotic therapy, and should be considered as a bridge to more definitive surgical repair at a later time, after optimization of the patient's condition.