Umbilical cord blood is rich in hematopoietic stem cells. At birth, it can be collected, HLA-typed and stored. Cord blood is successfully used since over 10 years as source of transplantation of hematopoietic stem cells, in addition to bone marrow and mobilized peripheral blood stem cells. Allogeneic transplantations are performed between HLA-identical siblings and from HLA-matched unrelated donors. Most recipients of cord blood are children with Leukemia or genetic disorders, but also increasingly adolescents and adults. Based on the promising results, cord blood banks with kryopreserved, HLA-typed cord blood samples from anonymous donors are set up worldwide, ready to be used as allogeneic stem cell graft. In addition, so-called "private" cord blood banks have been set up, providing the possibility to store cord blood at birth from healthy children with no affected family member for a possible autologous stem cell transplantation in the future if the child later develops a disease such as Leukemia. For several reasons, however, this procedure has been scientifically as well as ethically challenged. To date, there is no established indication for an autologous cord blood transplantation. Nevertheless, the plasticity and multipotency of adult stem cells, which has been recently discovered, could lead to a possible autologous use of cord blood stem cells for different indications in the field of regenerative medicine (cell- and organ replacement/regeneration). So far, however, this remains speculatative. Research in the field of stem cell development and differentiation in the next decade will try to find some answers.