The basis for native as well as therapeutic neovascularization is not restricted to angiogenesis but includes postnatal vasculogenesis. Our laboratory and others' have established that bone marrow-derived endothelial progenitor cells (EPCs) are present in the systemic circulation, are augmented in response to certain cytokines and/or tissue ischemia, and home to as well as incorporate into sites of neovascularization. Given the background, EPCs have been investigated as therapeutic agents in these studies of supply-side angiogenesis under pathological as well as physiological conditions. This review discusses the therapeutic potential of EPCs for cardiovascular ischemic diseases.