Allogeneic stem cell transplantation is the only curative treatment for Wiskott-Aldrich syndrome. The authors retrospectively analyzed the outcome with this procedure in 13 patients with severe Wiskott-Aldrich syndrome transplanted in 5 Spanish centers from 1989 to 2006. A patient was transplanted twice from the same donor due to a late engraftment failure. Age at transplant ranged from 7 to 192 months (median 30 months). There were 10 matched donors (3 related and 7 unrelated), 2 mismatched unrelated, and 1 haploidentical. Conditioning regimen consisted of busulfan and cyclophosphamide (BuCy) in 11 cases and fludarabine and melfalan (1) or BuCy (1). ATG was added in transplants from non-genetically matched donors. GvHD prophylaxis consisted of cyclosporine and methotrexate in most patients plus T-cell depletion in the haploidentical HSCT. Nine of the 13 transplanted patients are alive with complete clinical, immunologic, and hematologic recovery 8-204 months (median 101 months) after HSCT. Eight surviving patients had been transplanted from matched donors (3 related and 5 unrelated) and 1 from a haploidentical donor. Four patients died, 2 transplanted from matched donors (1 from acute GvHD and organ failure, 1 from a lymphoproliferative disorder after a second transplant), and 2 transplanted from mismatched unrelated donors (1 from acute GvHD and organ failure, 1 from graft failure and infection). Allogeneic hemopoietic stem cell transplantation must be utilized in all patients with severe Wisckott-Aldrich syndrome, using the most suitable graft variant for each patient.