Hematopoietic stem cell transplantation (HSCT) is now highly successfully curing a widening range of primary immunodeficiencies (PIDs). Better tissue typing, matching of donors, less toxic chemotherapy, better virus detection and treatment, improved supportive care, and graft-versus-host disease prophylaxis mean up to a 90% cure for severe combined immunodeficiency patients and a 70-80% cure for other PIDs given a matched unrelated donor, and rising to 95% for young patients with specific PIDs, such as Wiskott-Aldrich syndrome. Precise molecular diagnosis, detailed data on prognosis, and careful pre-HSCT assessment of infective lung and liver damage will ensure an informed benefit analysis of HSCT and the best outcome. It is now recognized that the best treatment option for chronic granulomatous disease is HSCT, which can also be curative for CD40 ligand deficiency and complex immune dysregulation disorders.