Wiskott-Aldrich Syndrome (WAS) is a sex-linked disease characterized by immunodeficiency and thrombocytopenia. Supportive treatment of this disease is inadequate and bone marrow transplantation has been reported to result in excellent survival. The long-term follow-up of 8 male patients who received bone marrow transplantation for the WAS is reported here. All of these patients received ablative preparative treatment consisting of ATS (antithymocyte serum), cytoxan and either busulfan or TBI (total body irradiation). Bone marrow was transplanted from an HLA-matched donor. Seven of eight of these male patients have had excellent engraftment of their transplant and now have adequate lymphocyte and platelet function. In addition, they have had good growth and development. This suggests that ablative preparative treatment followed by early bone marrow transplantation from an HLA-matched donor is a highly successful therapy for this congenital disease.