Regenerative medicine is often touted as an achievement of the new millennium, but many approaches to improve health by stimulating the organism's own capacity for healing have existed for a long time. Some components of today's regenerative medicine, however, are indeed fundamentally new developments, and one of those is the concept of increasing the number of contractile cells in the heart to cure heart failure, either by stimulating intrinsic regeneration processes or by transplanting exogenous cells. The aim of this paper is to review the current status of some key aspects of cell therapy and obstacles to clinical translation.