OBJECTIVES: To prospectively evaluate the diagnostic value of combined PET/CT in detecting a malignant tumor in patients with no previous cancer history, presenting with a pelvic mass. METHODS: From September 2004 to March 2006, 101 patients (median age=60 years, range=24-85 years) with a Risk of Malignancy Index (RMI)>150 based on serum CA-125, ultrasound examinations (US) and menopausal state, were referred to PET/CT within 2 weeks prior to standard surgery/debulking of a pelvic tumor.