A case of systemic amyloidosis involving the upper and lower gastrointestinal tract is presented. The initial manifestation of this case was bloody diarrhea. On colonoscopy, multiple submucosal hematomas and irregular ulcerations of the sigmoid and descending colon were found. The pathologic diagnosis was confirmed by an endoscopic mucosal biopsy of the gastrointestinal tract and the specimen revealed massive amyloid deposits in the wall of the upper and lower intestinal tract. With intensive medical treatment, the submucosal hematoma disappeared and the ulcerations decreased in size. However, on the 29th day, the patient was expired due to unexpected sepsis. (Korean J Gastrointest Endosc 19: 829∼833, 1999)