Ovarian cancer (OC) is the third most common gynaecologic cancer worldwide and has the highest mortality rate among gynaecologic cancers. Despite the advances in cytoreductive surgery and frontline chemotherapy, recurrence is a common event in the advanced disease setting, with more than 70% of women experiencing relapse within two years from diagnosis. New strategies to anticipate the diagnosis of recurrence have been investigated in the last years. In this context, standard serum biomarkers, such as CA-125, and radiological evaluation are commonly used for disease surveillance, However, the early identification of relapsed disease as well as the identification of patients at higher risk for recurrence are still unmetclinical needs. Novel and reliable molecular biomarkers, which might also better represent the intrinsic molecular complexity of OC, could help clinicians to address this important challenge. Circulating tumor DNA (ctDNA) analysis has recently emerged as a non-invasive tool to profile and monitor tumor evolution over time. CtDNA has been extensively studied in several neoplasms in order to evaluate its ability in anticipating detection of relapse compared to common markers used in clinical practice. Wehave designed a study to assess the ability of ctDNA to detect recurrence and progression of disease and to provide a genomic characterization, during follow-up of patients with advanced OC. If proven effective and reliable, ctDNA could be introduced into routine surveillance programme for OC.