A 77 year-old man developed intermittent diarrhoea and malabsorption. Endoscopic findings and preliminary histological examination indicated ulcerative colitis. Special staining of biopsies from the duodenum and colon revealed amyloid deposits. Classification of the amyloid fibril protein verified AL-amyloidosis, and the diagnosis primary idiopathic amyloidosis was made. Amyloid deposit in the gastrointestinal tract are a common feature of primary and secondary amyloidosis. The symptoms and findings are nonspecific and resemble those of chronic inflammatory bowel disease and ischemic colitis. Secondary amyloidosis can be seen as a rare complication of Crohn's disease and ulcerative colitis. Special staining is necessary to show amyloid deposit, and the distinction between primary and secondary amyloidosis requires immunohistochemistry.