Bone marrow is soft, gelatinous tissue that fills the medullary cavities, the centers of bones. The two types of bone marrow are red bone marrow, known as myeloid tissue, and yellow bone marrow, or fatty tissue. Studies have shown global and regional functional improvements after Bone Marrow Stem Cell (BMSC) have been injected into viable, peri-infarct areas of chronically ischemic myocardium. Bone marrow-derived CD34+ and CD 133+ cells, which exhibit endothelial phenotypes, have been shown to contribute to neovascularization. Also, intramyocardial injection of purified CD133+ BMSC that was involved in their direct application into the diseased myocardium at the time of Coronary Artery Bypass Graft (CABG). Bone marrow or mobilized peripheral blood progenitor cells might play a role in the revascularization of the ischemic myocardium. Those features may explain the improved Left Ventricular Ejection Fraction (LVEF) in patients with Chronic Myocardial Infarction (CMI). It has been shown that selected BMSC were more effective than unselected BMSC in the infarcted myocardium However, the therapeutic efficacy remains controversial. Hyeon Woo Yim, Are Selected Bone Marrow Stem Cells More Effective than Unselected Ones in Patients with Chronic Myocardial Infarction?