Oocytes retrieved from gonadotrophin-stimulated cycles in polycystic ovarian syndrome (PCOS) patients are of different quality and different developmental potential. We hypothesized that oocyte quality and fertilization potential might be related to the follicular fluid active renin and vascular endothelial growth factor (VEGF) concentrations. In this prospective study 20 patients with PCOS undergoing in vitro fertilization (IVF) (conventional IVF or intracytoplasmic sperm injection—ICSI) were included. Each follicular aspirate was analysed for active renin and VEGF. Oocytes and embryos were checked for quality. In empty follicular aspirates active renin concentrations were higher (mean difference: 0.05 pg/ml; range: 0.01 to 0.09 pg/ml; P=0.01) and VEGF concentrations were lower (mean difference: 169 pg/ml; range: 330 to −8 pg/ml; P=0.034) than in the aspirates containing normal appearing MII oocytes. Follicular fluid VEGF concentrations were lower in immature than in normal appearing MII oocytes (mean difference: −548 pg/ml; range: −1064 to −32 pg/ml; P=0.034). VEGF concentrations were higher in aspirates containing normal appearing MII oocytes that fertilized compared to those MII oocytes that did not (2238±691 vs. 1877±902 pg/ml; P=0.045). Differentiation of normal appearing MII oocytes that fertilize from those that do not might be the consequence of better expression and action of RAS substances and VEGF.