Meta-analyses and some randomized clinical trials have shown modest improvement in left ventricular function after intracoronary injection of bone marrow cells (BMC) in patients with acute myocardial infarction (AMI). This has been shown even though several limitations like ignorance about the best cell(s) to use, the optimal dose, an effective administration mode, and the mechanism of action remain. The potential of BMC therapy will not be realized until these hurdles are passed. And even though BMC therapy seems to be relatively safe, it is invasive and expose the patients to the possibility of procedure-related complications. Thus, at the current stage of development, it will probably be better to use resources on more basic research and small- to intermediate-sized clinical trials instead of a large-scale outcome trial.