Case of peritoneal tuberculosis in a 54-year-old woman with a history of type II diabetes mellitus, treated irregularly; who presented a clinical picture of abdominal distension, low weight, hyporexia, and diffuse ascites associated with omental edema. A CA-125 sample was taken with a presumed diagnosis of ovarian cancer, however, pathological studies by laparoscopy reported chronic granulomatous peritonitis of the tuberculoid type with caseous necrosis, referring to peritoneal tuberculosis, which is a rare diagnosis that represents 0 .1–0.5% of all cases of Tuberculosis. Peritoneal tuberculosis should be considered as one of the possible differential diagnoses in cases of patients presenting ascites with elevated serum CA-125 levels. However, to confirm the diagnosis it is necessary to obtain histological evidence that supports the presence of changes compatible with this disease. In ...