Regenerative medicine aims to restore homeostasis through a broad spectrum of strategies ranging from transplantation of donor organs to augmentation of innate healing processes. Its first clinical application emerged five decades ago when bone marrow-derived stem cells were used to replace defective progenitor cells. Since then, a variety of technological advances have expanded its scope. Most recently, the advent of natural or bioengineered stem cell products for tissue repair has inspired hope that the toughest obstacles in transplant medicine--the shortage of organs and organ rejection--might be overcome.This article describes the evolution of regenerative medicine and some of the ways it is being used in research and clinical practice.