Skeletal myoblast transplantation has now entered the clinical arena as a potential means of restoring function to scarred myocardium. While the current experience derived from phase I trials suggests that cell implantation during coronary artery bypass operations is a straightforward and safe procedure, routine use of myoblast transplantation would certainly be premature. Two major issues have not yet been addressed: firstly, the risk -benefit ratio needs to be assessed, specifically whether the potential proarrhythmic risk associated with myoblast transplantation is supported by the results of an ongoing large, randomized study, and if so, whether this risk is offset by a benefit in terms of improvement of left ventricular function and patient outcome. Secondly, this putative benefit will then have to be weighed against the financial burden inherent to this type of procedure, to assess whether the cost -effectiveness ratio is favorably shifted and supports the expanded indication of myoblast transplantation during coronary artery revascularization in patients with severe ischemic heart failure. © 2006 Nature Publishing Group.