Primary immunodeficiencies constitute a group of highly complex congenital disorders most of which are characterized by poor prognosis with high mortality and morbidity. Hematopoietic SCT became an established therapy for such disorders. The first clear-cut report of successful allogenic SCT in 1968 dealt with the treatment of a patient with primary immunodeficiency, that is, SCID and Wiskott-Aldrich syndrome. Starting with this pioneering experience in 1968, hundreds of SCID patients and hundreds of patients affected by other life-threatening forms of primary immunodeficiency throughout the world have benefited from SCT. Presently, hematopoietic SCT from an HLA-matched sibling donor confers at least 80% chance of cure for children affected by primary immunodeficiency and about a 70% chance of cure when a fully HLA-matched related donor is available. This high success rate is the consequence of better management of nutrition and the infection problem affecting these patients at the time of disease. Conversely, when a related HLA-mismatched donor is used, the survival rate is significantly lower than that of patients receiving SCT from either an HLA-matched sibling or a fully matched HLA-unrelated donor. Optimal results and outcome of SCT are highly dependent on early and correct diagnosis of these disorders. SCT should be applied early in the course of the disease to prevent irreversible complications from the primary disease and/or infection. We present the data on outcome for primary immunodeficiency transplantation at King Faisal Specialist Hospital from 1993 to 2006.