An 81-year-old man with history of hypertension and chronic renal insufficiency was admitted to a hospital because of diarrhea and melena. The patient was diagnosed as inflammatory bowel disease (IBD) by colonoscopy and was given predonisolone and mesalazine. He was transferred to our hospital three days later following emergence of respiratory failure and anuria. The cause of these organ failures was digestive tract perforation and sequential panperitonitis. An emergency subtotal colectomy and ileostomy was done and the patient was pathologically diagnosed as amoebic colitis. Postoperative course was complicated by severe Aspergillus pneumonia. Combination therapy of antibiotics and antifungals could not improve his pneumonia and the patient passed away on the 12th ICU day. Amoebiasis sometimes develops without apparent history of chance of infection. Insufficiency of immune system of any kinds was supposed to be a determinant. Complications like Aspergillus pneumonia in this case may relate to immuno-insufficiency of the patient. Amoebiasis itself has good outcome unless digestive tract perforation occurs. Amoebiasis must be considered in differential diagnosis of idiopathic IBD and its early diagnosis and treatment should be important for better outcome.