Endothelial progenitor cells (EPCs) are a circulating, bone marrow-derived cell population that participate in both vasculogenesis and vascular homeostasis.Recent studies have shown that EPCs are reduced by ~ 50% in diabetes that correlates inverse ly with its mortality rate.In addition, EPC angiogenic functions are severely impaired in diabetes.However, the molecular and cellular mechanisms underlying EPC dysfunction are poorly understood.Our current studies have focused on in vitro and in vivo aspects of oxidative stress regulation of EPC dysfunction and an giogenesis in diabetes.