The ultimate aim of stem cell research is to improve patient outcomes and quality of life, and/or to effect a cure for a variety of inherited or acquired diseases. Improved treatments rely on developments in stem cell therapies and the discovery of new therapeutic drugs that regulate stem cell functions. These complement each other for the repair, regeneration and replacement of damaged or defective tissues. Stem cells may be sourced or derived from blood and tissues postnatally ('adult' stem cells), from the fetus (fetal stem cells) or from the blastocyst in the developing embryo prior to implantation (embryonic stem cells), each forming a unique component of the revolution in stem cell research and therapies. This review will concentrate on recent developments in the use of haemopoietic stem cells from umbilical cord blood for the transplantation of patients with haematological disorders. It will conclude with a summary of the potential of other umbilical cord blood-derived stem cells for tissue repair or regeneration.