Stem cell research is a global phenomenon; understandably, each country has its own system of regulation (or lack of). Bodies have been established to promote good working practice in stem cell research across the world. Two of the most prominent are the International Society for Stem Cell Research (ISSCR) and the International Stem Cell Forum (ISCF). The ISSCR has produced two documents to help establish good working practices internationally: Guidelines for the Clinical Translation of Stem Cells and Guidelines for the Conduct of Human Embryonic Stem Cell Research recommend appropriate conduct while recognizing different international perspectives. The International Stem Cell Banking Initiative (ISCBI) is also working on establishing best practice globally in stem cell banks.Stem cells have the remarkable capability to self-renew in an undifferentiated state and to differentiate into many types of cells with specific functions upon receiving appropriate triggers. In this article, five different types of stem cells are discussed: human embryonic stem cells, human-induced pluripotent stem cells, neural stem cells, mesenchymal stem cells, and hematopoietic stem cells. We describe their initial discovery, sources where they are obtained and niches where these stem cells reside, the canonical phenotypic markers for distinguishing them, their lineage differentiation capabilities, and review some key clinical trials that are ongoing for each of these important stem cell types.