In 2007, the Nobel Prize in Physiology and Medicine was awarded to Martin Evans, Mario Cappecchiemu and Olivier Smithiesowi. Martin Evans has been honored for the isolation of pluripotent mouse embryonic stem cells (ES cells), two other researchers for developing methods of genetic modification of these komórek.Tutaj presents the history of obtaining embryonic stem cells, methods of inducing their differentiation targeted in vivo and in vitro, as well as selected issues associated with the potential use of these cells for therapy. Also discussed the techniques used for the genetic modification of ES cells and the latest scientific achievements by which it is possible to obtain pluripotent cells not only from embryos at early stages of development, but also from somatic cells.