Anaplastic large cell lymphoma (ALCL) is chemosensitive, but recurrence is frequently observed. Allogeneic hematopoietic stem cell transplantation (HSCT) has recently been reported to be effective against recurrent disease, suggesting a graft-versus-lymphoma effect. We present a 3-year-old child with recurrent ALCL who underwent HSCT from an HLA-1-locus mismatched cord blood unit following reduced intensity conditioning with fludarabine, melphalan, and low-dose thoraco-abdominal irradiation. Engraftment was uneventful, but grade III acute graft-versus-host disease was observed. He is well and free of disease 25 months after HSCT, which implies that reduced intensity conditioning may allow a sufficient graft-versus-lymphoma effect against ALCL while lessening treatment-related toxicities.