The conservation of the cells mother of the umbilical cord one has become, in just a short time, in a question of interest for many parents, who see in this practice the possibility of doing in the future against possible diseases of their children. But, To what extent this practice contributes benefits? We must choose a public or deprived bank of preservation? What problems the patients can be faced? Which can be the benefits for the patients? " The use of the blood of the umbilical cord is used to carry out alognico transplant, generally of nonfamiliar donor, although also of familiar donor. This type of transplant has advantages and disadvantages with respect to the use of cells obtained from the bony marrow or the blood of a donor The main advantage is that the transplants of umbilical cord blood are tolerated well although is low compatibility of human leucocytary antigen (HLA), reason why can be units valid, for the majority of the patients. One of the problems of its use it derives from the little amount of cells that there are in the small amount of blood that can be obtained from the umbilical cord after new born it is had separated of the placenta by section of cordn". What guarantees of success have the use of cells mother of the cord umbilical against other more conventional treatments? " The main advantage is the one of which the transplants of umbilical cord blood are tolerated or although have low compatibility HLA, that is to say, it is not essential to respect the barrier of histocompatibility with as much exigency as it happens when the transplant with obtained cells of the marrow or the blood of a donor is carried out. This is a great advantage because sometimes it is not had totally compatible donors, especially in certain ethnic groups.