Autoimmune pancreatitis has recently been described as a clinical entity that causes chronic pancreatitis. This unique form of chronic pancreatitis is characterized by minimal attacks of abdominal pain, irregular narrowing of the pancreatic duct, and a diffuse enlargement of the pancreas. Autoimmune pancreatitis is associated with hypergammaglobulinemia. In addition, there is histological evidence of lymphoplasmacytic inflammation, the occasional coexistence of other autoimmune diseases, and has a favorable response to glucocorticoid treatment. Recently autoimmune pancreatitis has been increasingly reported particularly in Japan. We report two patients with autoimmune pancreatitis who were treated successfully with corticosteroid therapy.