We report the results of 39 children who underwent cord blood stem cell transplantation (CBSCT) at our institute during the period from February 1996 to July 2005. The patients consisted of 9 with non-malignant disease, 26 with malignant disease and 4 with Epstein-Barr virus (EBV) associated disease. The median age of the patients was 4 years and 8 months (range, 6 months to 16 years 2 months). The median infused cell dose was 4.9 (range, 1.7-11.4) x 10(7)/kg. Thirty-four transplants were from HLA-mismatched donors, and 33 patients underwent a tacrolimus-containing regimen for GVHD prophylaxis. As for CBSCT as the first transplant, 3 out of 4 children with non-malignant disease achieved engraftment after CBSCT with the use of a reduced-intensity conditioning regimen. For acute leukemia, 3 patients out of 5 in their first remission and 2 out of 9 in advanced stage at CBSCT continue in remission at the time of writing. Fourteen patients received CBSCT as a second or a third transplant. None of 4 patients who underwent CBSCT as rescue therapy after rejection/graft failure achieved engraftment. It should be emphasized that EBV-associated disease seems to be a suitable disease for CBSCT, because all of the 4 patients who underwent CBSCT are still in CR.