A successful cord blood transplantation combined with hematopoietic growth factor was performed in a boy presenting with refractory mediastinal T-cell lymphoma. Cord blood cells were collected from an HLA-identical sibling at the time of delivery. A transient and corticosensitive acute grade II graft versus host disease was observed. One year after transplantation, the child is still in remission with complete engraftment. This is the first report of cord blood transplantation in a patient with refractory lymphoma.