Platelet-to-lymphocyte (PLR) and Neutrophil-to-Lymphocyte (NLR) ratios have been extensively investigated in cancer. However, to date, actual guidelines concerning ovarian cancer are missing. The purpose of the present systematic review is to summarize the available evidence. We systematically searched Medline (1966-2016), Scopus (2004-2016), ClinicalTrials.gov (2008-2016), and Cochrane Central Register of Controlled Trials CENTRAL (1999-2016) databases together with reference lists from included studies. Eighteen studies were included in the present systematic review that involved 3453 patients. According to the current data, both PLR and NLR values in ovarian cancer patients seem to deviate from healthy controls. Furthermore, they may also be indicative of the stage of the disease and of the response to chemotherapy. Nevertheless, their diagnostic accuracy remains limited as their sensitivity and specificity are moderate (detects 55-80% of ovarian cancer women). According to the findings of our study, both PLR and NLR seem to be promising screening and prognostic factors of epithelial ovarian cancer. The actual diagnostic cut-off values remain, however, undefined until now. Despite their limited sensitivity and specificity, they might be useful in the future as adjunct biomarkers for the detection and surveillance of the disease.