The number of umbilical cord blood transplants (UCBT) is increasing worldwide, and the purpose of Eurocord is to evaluate the results and compare the outcome of UCBT with allogeneic bone marrow transplants (BMT). Data have been reported to Eurocord by many transplant centers. Close links have been established with cord blood banks through Netcord. BMT data have been provided by transplant centers and also by the European Blood and Marrow Transplant (EBMT) and International Bone Marrow Transplant Registries (IBMTR). Eurocord has analyzed the outcome of unrelated UCBT from 121 transplant centers and 29 countries. The results have shown that survival with unrelated mismatched UCBT was comparable to that with unrelated BMT. Engraftment with cord blood was delayed, resulting in an increased incidence of early transplant complications. The incidence of acute and chronic graft-versus-host-disease (GVHD) was reduced with cord blood grafts even in HLA mismatched transplants and in adults. In patients with leukemia, the rate of relapse was similar to that after BMT. The overall event-free survival with UCBT was not statistically different when compared to BMT. In conclusion, this large registry study confirms the potential benefit of using umbilical cord blood hematopoietic stem cells for allogeneic transplants.