Recently published reports indicate that the outcome of unrelated donor transplantations in patients with leukemia is currently comparable to that of transplantation from identical family donors. We investigated the possibly favorable outcomes of related and unrelated transplantation in children with severe thalassemia. We reviewed transplantation outcome in 49 consecutive children with severe thalassemia who underwent allogeneic stem cell transplantation with related-donor (n=28) and unrelated-donor (n=21) stem cells between September 1992 and May 2005 at the Faculty of Medicine, Ramathibodi Hospital, Mahidol University (Bangkok, Thailand). Analysis of engraftment, frequency of procedure-related complications, and thalassemia-free survival showed no advantage from use of related-donor stem cells. The 2-year thalassemia-free survival estimate for recipients of related-donor stem cells was 82% compared with 71% in the unrelated-donor stem cell group (P=.42). The present study provides evidence to support the view that it is quite reasonable to consider unrelated-donor stem cell transplantation an acceptable therapeutic approach in severe thalassemia, at least for patients who are not fully compliant with conventional treatment and do not yet show irreversible severe complications of iron overload.