The surveillance of ovarian cancer patients after initial treatment is a challenging question in clinical practice. Serum CA 125 assay, physical examination, and imaging examinations have been employed with different time schedules for the follow-up of asymptomatic patients. Rising serum CA 125 levels may precede the clinical detection of relapse in 56-94% of cases with a median lead time of 3-5 months. An ongoing randomised phase III European trial is comparing the benefits of early administration of chemotherapy based on serum CA 125 assay alone versus delaying treatment until clinical or radiological detection of recurrent disease. Physical examination, with or without ultrasound, is very useful for the surveillance of these patients, since approximately 25-50% of relapses involve the pelvis. Additional radiological imaging techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI), are usually performed in asymptomatic patients with rising CA 125 levels as well as in patients with suspicious symptoms or signs. Integrated positron emission tomography (PET) and CT scanners (PET/CT) can identify recurrent disease in tissues that appear normal at CT imaging as well as metastatic lesions intimately associated with the bowel wall that are difficult to detect with CT or MRI, so that in most series PET/CT has a higher diagnostic reliability than that of conventional imaging techniques. Moreover, PET/CT can disclose unusual supra-diaphragmatic spreading of the disease and may be very helpful for treatment planning, especially for the selection of patients suitable for secondary surgical cytoreduction. A prospective, randomised trial of therapeutic interventions based on stratification by PET/CT disease status could elucidate the real impact of this diagnostic procedure in the management of patients with recurrent ovarian cancer.