Vascular endothelial growth factor (VEGF) is a powerful mediator for vessel permeability and it is strongly implicated in angiogenesis, stimulating endothelial cell proliferation as well as capillary permeability. We studied 30 women undergoing in vitro fertilization (IVF) programs and evaluated, on the day of oocyte retrieval, VEGF levels in plasma and follicular fluid and related such concentrations to the amount of follicle-stimulating hormone (FSH) administered. Furthermore, the correlation between the number of oocytes retrieved and the VEGF concentrations both in plasma and in follicular fluid were also investigated.Results indicate that follicular fluid VEGF concentrations and the amount of pure FSH administered were directly proportional (p < 0.05). On the day of oocyte retrieval, the VEGF plasma concentrations and the number of oocytes collected were directly proportional (p < 0.05). VEGF plasma levels increased after human chorionic gonadotropin (hCG) administration (30.37± 18.60 pg/ml up to 52.62 ± 43.63 pg/ml).In conclusion, this study demonstrates that the doses of pure FSH administered to women undergoing IVF cycles have a crucial role in hCG-dependent VEGF production.