To investigate the roles of endothelin-1(ET-1), TNF-alpha, IL-6 in the pathogenesis of proliferative diabetic retinopathy (PDR) in type 2 diabetes.Vitreous and blood serum samples were collected during vitrectomy from 19 patients with PDR and 15 patients who underwent vitrectomy for other reasons. The concentrations of ET-1, TNF-alpha, IL-6, vWF, sE-selectin were determined by ELISA.Intraocular and serous concentrations of ET-1, TNF-alpha, IL-6, vWF, sE-selectin were higher in patients with PDR than in the control group. The vitreous ET-1/plasma ET-1 ratios the group of diabetic patients and in the control group were similar. Also TNF-alpha, IL-6 vitreous/plasma ratio were not statistically different between the analysed groups. Correlation between intraocular ET-1 and TNF-alpha concentrations in patients with PDR and between the increases in both factors in the vitreous and HbA(1)c concentration were shown. In the vitreous the increase in vWF depended on elevated levels of vWF in the serum. E-selectin concentration correlated with diastolic blood pressure.These data provide evidence of the activation of the local synthesis of ET-1, TNF-alpha, IL-6 in PDR. The relationship between the increase in vitreous ET-1, TNF-alpha concentrations and HbA(1)c concentration is a important confirmation of the necessity to optimise diabetes treatment.