Umbilical cord blood transplantation (CBT) is an alternative allogeneic haematopoietic stem cell transplantation (HSCT) strategy for patients with haematological diseases who do not have a matched related or unrelated donor and who need urgent transplantation. The value of CBT using myeloablative preparative regimens has already been confirmed among paediatric and adult patients (Laughlin et al, 2004;Rocha et al, 2004;Takahashi et al, 2004). However, conventional myeloablative preparative regimens are associated with significant morbidity and mortality, particularly in older patients or in those who have experienced extensive prior therapy or organ dysfunction associated with transplantation-related mortality. Various reduced-intensity preparative regimens that have been applied to such patients by several groups, including the authors of the present study, have proven feasible (Barker et al, 2003(Barker et al, , 2005Chao et al, 2004;Jacobsohn et al, 2004;Miyakoshi et al, 2004Miyakoshi et al, , 2007Yuji et al, 2005;Misawa et al, 2006;Ballen et al, 2007;Brunstein et al, 2007;Komatsu et al, 2007;Uchida et al, 2008).