We report colonoscopic findings in 29 proven cases of segmental colonic tuberculosis. The colonoscopic appearances of tuberculosis included: mucosal nodules and ulcers, stricture with nodules and ulcerations, and mucosal nodules with or without pseudopolypoid folds. In 12 (41%) of 29 patients colonoscopy biopsies enabled a histologic diagnosis to be made on the basis of typical granulomas. Culture of biopsy tissue on Lowenstein Jensen media isolated Mycobacterium tuberculosis in six (40%) of 15 patients. Combined histologic and bacteriologic evaluation established the diagnosis in 60% of patients. We conclude that even though target biopsy is an effective method of diagnosis, anti-tuberculous chemotherapy may be started on the basis of the endoscopic appearance if there is a high clinical suspicion of tuberculosis.