Tuberculous peritonitis is rare in most Western counties, and can cause significant diagnostic and therapeutic problems. A 28-year-old pregnant female presented with nausea and vomiting, right lower quadrant abdominal pain, fever and intra-abdominal fluid. During surgery for presumed complicated acute appendicitis, many small masses (considered to be ‘implants’) were found within the peritoneal cavity, with a larger mass in the pelvis, mainly on the right. The clinical intra-operative diagnosis was advanced ovarian cancer and multiple biopsies were taken. The histological diagnosis was peritoneal tuberculosis. The patient was successfully treated conservatively. Hasty decisions to undertake radical and irreversible surgery should be avoided; this type of surgery should be performed only after histological confirmation.