AIM: To evaluate serum concentrations of visfatin, vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) in women with polycystic ovary syndrome (PCOS) and to investigate their possible role as early endothelial markers in PCOS.METHODS: Forty-two women with PCOS and 42 controls, matched for age and weight, were included in the study. Serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, total testosterone (tT), Δ-androstenedione (ΔA), dehydroepinadrosterone sulphate (DHEA-S), 17-OH-progesterone, sex hormone-binding protein (SHBG), thyroid-stimulating hormone (TSH), free thyroxine (fT), visfatin, VEGF and MMP-9 were measured in all women; free androgen index (FAI) was calculated as well. Receiver-operating characteristic (ROC) analysis was performed to examine if visfatin, tT or FAI can predict the clinical status (PCOS or control).RESULTS: LH, ΔA, tT and FAI concentrations were higher in PCOS than in controls (p = 0.002, 0.029, 0.0005 and 0.014, respectively). Visfatin, VEGF and MMP-9 concentrations were higher in women with PCOS than controls (p = 0.019, 0.001 and 0.002, respectively). In ROC analysis, area under the curve (AUC) in the prediction of clinical status was 0.641 for visfatin (p = 0.026), 0.731 for tT (p = 0.001) and 0.666 for FAI (p = 0.010), with no difference among them (p = 0.117).CONCLUSIONS: Visfatin may induce the expression of pro-angiogenic factors, such as VEGF and MMP-9, in women with PCOS, inplying gradually development of endothelial dysfunction. Further studies are required to clarify these findings.