Gastrointestinal hemorrhage is an infrequent but well recognized complication in patients with pancreatitis. Pancreatitis, peripancreatic inflammation and established pseudocysts can lead to pseudoaneurysm formation of contiguous splanchnic arteries which may cause significant gastrointestinal hemorrhage. Hemorrhage from a ruptured pseudoaneurysm may occur into various parts of gastrointestinal tract and present major clinical problems, both in terms of timely diagnosis and appropriate surgical therapy. Lower Gastrointestinal hemorrhage caused by ruptured pseudoaneurysm is extremely rare and has a worse prognosis, mainly because of the high incidence of fulminating sepsis and massive bleeding. We experienced a case of massive lower gastrointestinal bleeding caused by pseudoaneurysrnal rupture of splenic artery into colon in a patient with chronic pancreatitis. (Korean J Gastroenterol 1997; 30:268-272)