The aim of the study was to assess the predictive value of vascular endothelial growth factor (VEGF), its soluble receptor - sVEGF-R1/sFlt1 and endocrine gland-derived vascular endothelial growth factor (EG-VEGF) concentrations in serum and follicular fluid (FF) for ovarian hyperstimulation syndrome (OHSS) in women undergoing controlled ovarian hyperstimulation (COH) protocols.