An isolated tuberculous lesion of the large bowel beyond the caecum is a rarity even in countries where tuberculosis of the intestinal tract is not uncommon. Chawla, Mukerjee and Bery (1971) report only ten cases of isolated lesions of the large bowel beyond the caecum in over 750 cases of tuberculous enterocolitis, and Bhansali (1968) reports three cases of isolated colonic involvement beyond the caecum in 87 cases of intestinal tuberculosis. The formation of internal fistulae in these cases is very rare. We are reporting a case of isolated segmental tuberculosis of the sigmoid colon complicated by entero-colic fistula in an Asian immigrant seen at the Coventry Group of Hospitals, where pre-operatively the diagnosis was mistaken for Crohn's disease.