Arterio-enteric fistula is a rare, but potentially deadly cause of gastrointestinal bleeding. The disease occurs in two forms: primary as a result of atherosclerotic aortic aneurysm, aortitis, trauma, radiation, tumor invasion or penetrating ulcer, and secondary as a consequence of surgical aortal reconstruction. The clinical manifestation is mostly gastrointestinal bleeding, rarely back pain, fever and sepsis. Computed tomography with contrast medium is the most suitable diagnostic test, however, the diagnosis frequently requires explorative laparotomy. A case is presented of secondary arterio-enteric fistula, found two years after surgical treatment of chronic pancreatitis with pseudocystojejunostomy, which clinically manifested with gastrointestinal bleeding. Although there was strong suspicion of arterio-enteric fistula, the diagnosis was not verified by routine workup, but only on explorative laparotomy.