We report a patient with reactive systemic AA amyloidosis secondary to rheumatoid arthritis who showed fatal acute pancreatitis with a cystic formation in the pancreas head. The pancreatitis rapidly worsened despite intensive treatment and resulted in death. In this patient severe deposition of amyloid in the gastrointestinal tract was considered to play an important role in the pathogenesis of the acute pancreatitis. This is an unusual complication in patients with AA amyloidosis, but we should consider it as a possible diagnosis when patients with AA amyloidosis show recurrent or intractable pain in the upper abdomen.