Gastrointestinal tuberculosis and tuberculous peritonitis are still considered a rare disease in Japan. A high index of suspicion must be maintained to make an exact diagnosis. It also must be kept in mind that little evidence of active or healed tuberculosis is detectable on chest x-ray. The jejunoileum and ileocecum are most commonly affected in the gastrointestinal tuberculosis. Abdominal pain and abdominal tenderness are present in most patients. An abdominal mass is often palpable in the right lower quadrant. The most valuable diagnostic study is colonoscopy with biopsies. In tuberculous peritonitis, an abdominal swelling is the most common symptom. Laparoscopy with directed biopsy is an excellent study for diagnosis. The levels of ascites adenosine deaminase are also useful for diagnosis.