A cord blood graft is now frequently used in the context of allogeneic hematopoietic transplantation. In 2007, 27% of unrelated allotransplantations performed in France used a cord blood graft. In comparison to other sources of hematopoietic grafts, cord blood has a number of advantages (immediate availability of the graft, possibility of a lesser HLA compatibility between donor and recipient...) and inconveniences (a limited number of stem cells, increased risk of infectious complications...). Recently, the possibility of combining two cord blood grafts has been demonstrated. In 2007, 55% of unrelated cord blood grafts transplantation were performed as such. Results of multicentric studies published as of now, as well as considerable potential associated with cord blood transplantation requires important efforts to increase both the quantity and quality of cord blood grafts made available for transplantation.