Objective To investigate the amounts of endothelial progenitor cells (EPCs) in peripheral blood of patients with proliferative diabetic retinopathy (PDR). Methods Forty patients with PDR (PDR group), thirty patients with type 2 diabetes mellitus (DM) without DR (DM group), and twenty age-matched normal subjects (control group) were enrolled in this study. Blood samples were treated by repeated centrifugation and stained with monoclonal antibodies. At least 2times;105 cells were analyzed by flow cytometry. EPCs were identified by CD34 and CD133 antibody. The correlation between EPCs numbers and DR duration, glycosylated hemoglobin, serum lipids was analyzed. Results The number of EPCs in PDR, DM and control group were (49plusmn;12)、(35plusmn;11)、(90plusmn;25) cells/ml respectively, the difference was statistically significant (F=56.260, P=0.000). There was a positive correlation between EPCs numbers and DR duration (r=0.564, P＜0.05). However there was no correlation between EPCs numbers and glycosylated hemoglobin (r=-0.170, P＞0.05) or triglyceride levels (r=0.261, Pgt;0.05). Conclusions The number of EPCs in peripheral blood of PDR patients was decreased. EPCs might play an important role in the pathogenesis of PDR.