Postnatal neovascularization was initially thought to result exclusively from the migration and proliferation of pre-existing, fully differentiated endothelial cells (a process referred to as angiogenesis). Several lines of experimental evidence, however, demonstrated that circulating endothelial progenitor cells (EPCs) home to sites of neovascularization and differentiate into endothelial cells in situ in a manner consistent with a process termed vasculogenesis. Moreover, recent clinical study, named as the Therapeutic Angiogenesis Using Cell Transplantation (TACT), has demonstrated the efficacy and safety of autologous implantation of bone marrow-mononuclear cells(BM-MNCs) in randomly allocated patients with ischemic limbs of peripheral arterial diseases. Implantation of BM-MNCs is also applied to patients with no-option angina pectoris, demonstrating the usefulness of this therapy for improvement of symptom, myocardial perfusion, and exercise capacity. Moreover, recent accumulating studies demonstrated the possibilities that transplantation of bone marrow-derived or peripheral blood-derived EPCs enhances neovascularization and improves cardiac function after acute myocardial infarction(AMI). There were no serious adverse effects reported in cell transplantation therapy. Thus, bone marrow-derived cell transplantation therapy has been applied to acute and chronic ischemic heart diseases as well as peripheral arterial diseases, demonstrating the safety and effectiveness of therapeutic angiogenesis.