Findings in the last decade suggest that there is a considerable amount of cardiomyocyte turnover in the human heart throughout life, albeit not sufficient for heart regeneration following myocardial infarctions. Only a few species are known to be remarkably efficient in cardiac regeneration. They restore lost cardiomyocytes via a process of cardiomyocyte dedifferentiation, which is followed by robust proliferation of cardiomyocytes and incorporation into the myocardium. Similarly, neonatal mice have been recently shown to regenerate their heart following myocardial injuries. Studies with a neonatal cardiac regeneration mouse model suggest that the major source of new cardiomyocytes is likely to be of cardiomyocyte origin, with the possibility of involvement of cardiac stem cells. To this end, numerous studies have been conducted on the induction of cardiac regeneration to shed light on the underlying mechanisms. This review covers studies on the renewal of cardiomyocytes, the utilization of stem cells in myocardial therapies, and their future applications.