This study represents the clinical and laboratory features of 135 tuberculous peritonitis cases in whom peritoneoscopic investigation was used routinely. Disease was more common in women than men (1.5:1) and was most frequently encountered in the third and fourth decades in life. The most common presenting symptoms were abdominal distension (96%), abdominal pain (82%), weight loss (80%), weakness (76%), loss of appetite (73%) and fever (69%). The most common physical findings were ascites (96%), fever (75%) and abdominal tenderness (43%). One hundred and twenty-nine cases (95.5%) showed exudative type tuberculous peritonitis with variable amounts of ascites and filmy adhesions. In six patients (4.5%) the disease was of the plastic (dry) type. Peritoneoscopic investigations of 139 patients suggested tuberculous peritonitis but four cases showed histologically proven malignancy (3%). Laparoscopic diagnoses of the remaining cases were confirmed by histology (97%). The laparoscopic appearance of scattered yellowish-white nodules, approximately 1-5 mm in size, on the peritoneal surfaces, and filmy adhesions were suggestive of tuberculous peritonitis. A non-fatal colon perforation occurred as a major complication. After antituberculous therapy patients were followed for at least 1 year. Peritoneoscopy with simultaneous biopsy is the ideal and most accurate diagnostic modality in the diagnosis of tuberculous peritonitis.