Human umbilical cord blood (HUCB) represents a unique source of transplantable hematopoietic progenitor cells. HUCB from a newborn sibling has been used successfully for hematopoietic reconstitution of more than 50 children with congenital and malignant diseases. Moreover, 13 HUCB transplants have been performed from unrelated donors. Bone marrow transplantation (BMT) has rapidly progressed over the last two decades offering cure and prolonged disease free survival in patients with hemato-oncological malignancies, metabolic and genetic disorders. BMT is limited by the paucity of HLA-matched donors and the morbidity and mortality due to graft-versus-host disease (GVHD). HUCB could alleviate some of the problems associated with BMT and establishment of HUCB bank and registries could become an easily available source of suitable stem cells for transplantation. This review focuses on identifying current scientific problems and clinical achievement as well as noting the most recent developments in the field with special attention to the collection, processing, cryopreservation, and banking of HUCB. Progenitor cells from cord blood may provide an excellent vehicle for future gene therapy. As a result of relative immunodeficiency at birth, it is likely that partially matched unrelated cord blood transplants (CBT) would be successful due to a lower risk of GVHD related problems. Therefore, the establishment of large cord blood banks is of the utmost importance, in the future.