Segmental tuberculosis of the colon is a rare clinical entity. In the absence of pulmonary or ileocecal involvement, colonic tuberculosis may be difficult to differentiate from neoplasm or Crohn's disease by symptomatic and radiological means. Colonoscopy and biopsy can, however, establish the diagnosis and prevent operative intervention, as indicated in the present report. A patient with a radiologically demonstrated strictured lesion of the sigmoid colon was found at colonoscopy to have several hemorrhagic transverse ulcers ranging in diameter between 1-4.5 cm. Multiple target colonoscopic biopsies, specifically from the ulcer beds, revealed necrotizing granulomas and acid-fast bacilli. Antituberculous chemotherapy produced remarkable symptomatic, radiographic and endoscopic improvements and averted exploratory laparotomy for the establishment of the diagnosis. This case report points out the importance of colonoscopic biopsy as a useful diagnostic modality in this disease.