Abstract: Objective To investigate the correlation between the number and activity of circulating endothelial progenitor cells (EPCs) and macrovascular complication of patients with type 2 diabetes mellitus. Methods 89 T2DM subjects were divided into macrovascular complication group(MVC) and noncomplication group(NMVC),and 27 healthy subjects were controls. Circulating EPCs were counted via fluorescenceactivated cell sorter analysis. EPCs were also isolated from peripheral blood and cultured in vitro for 7 days, then identified. EPCs migration activities and proliferation activities were determined. ResultsCirculating EPCs number was significantly lower in MCV group than in NMCV group[(0.37±0.03)‰ vs (0.46±0.06)‰,P<0.01]and control group (P<0.05). HOMAIR index and HbA1c were negatively correlated with number of circulating EPCs and proliferation and migration capacities of EPCs and also significantly lower in MCV group than in NMCV group (all P<0.05) and control group (all P<0.05). ConclusionsInsulin resistence and highglucose are related to the occurrence and development of macrovascular complication of patients with T2DM possibly via reducing the number and activities of circulating EPCs.