Umbilical cord blood (UCB) has become an alternative source of hematopoietic progenitors (HSC) for transplantation. Although most CB transplants have been performed in children, unrelated donor-cord blood transplants in adults have been growing steadily in recent years. HSC content of CB units influence significantly the transplantation outcome, as shown by many clinical studies. UCB banks are fundamental to support this increasing clinical activity and one of their main goals must be to store good quality units. Strategies for increasing HSC content of UCB units are reviewed and also its influence on transplantation outcome. Our bank selected the UCB units for cryopreservation on the basis of their total nucleated cells (TNC) and CD34+ cells content. We also reviewed the results of our UCB bank program.