Fistula between the arterial system and the gastrointestinal tract is rare, but can give rise to life-threatening bleeding. The fistula may be primary or secondary. A review of cases in the literature is presented and a classification based on type and cause is proposed. The collected series comprised 249 cases of primary, and 631 of secondary arterioenteric fistula. The dominant cause was aortic aneurysm in the primary and vascular reconstructive surgery in the secondary cases. As the prognosis is poor and aortoiliac reconstructive surgery is increasingly performed, awareness of arterioenteric fistula as a possible cause of gastrointestinal haemorrhage is important.