We studied 36 patients with gastrointestinal tuberculosis: 21 had peritonitis, 11 had enteritis, and four had both. Diagnostic criteria were (1) caseating granulomas or positive smear or culture from an abdominal specimen; (2) culture-proved pulmonary tuberculosis plus ascitic fluid containing protein, greater than 3.0 g/dL, and more than 50% lymphocytes, or granulomatous enterlitis on x-ray studies that resolved with antituberculous therapy. In only four of 15 patients with enteritis was the disease confined to the ileocecal region. Fourteen patients (40%) had complications: bowel obstruction in ten, perforation in six, and fistula in five. Five of these died. Two perforations and one death followed paracentesis and needle biopsy. Tuberculous peritonitis can be diagnosed without biopsy when lymphocytic exudative ascites responds to antituberculous chemotherapy given for concurrent culture-proved pulmonary tuberculosis. Patients with pulmonary tuberculosis and persistent abdominal complaints who have granulomatous enteritis should be considered to have tuberculous enteritis. Surgery is reserved for bowel obstruction, perforation, fistula, or a mass that does not resolve with drug therapy.