Peritoneal tuberculosis (TB) is still a major health problem in developing countries. We describe a 26-year-old woman with peritoneal TB presenting with lower abdominal pain and distention, weight loss, and night sweats. There are no pathognomonic clinical, laboratory, or radiologic findings for peritoneal TB. Therefore, it can be easily confused with peritoneal carcinomatosis and advanced ovarian carcinoma. Adenosine deaminase activity in ascitic fluid combined with a high clinic suspicion is an effective and minimally invasive procedure for the differential diagnosis of pelvic-peritoneal TB simulating peritoneal carcinomatosis, and may obviate the need for unnecessary extensive surgery and rapidly initiate appropriate therapy.