Bone marrow (BM) transplantations performed between 1977 and 1991 at 13 European centers in 149 patients with 11 different primary immunodeficiency (ID) diseases (excluding severe combined immunodeficiency) were analyzed retrospectively. Overall survival among recipients of HLA genetically identical BM (n = 56) was 66%. Since October 1985, the date of a previous survey, a significant improvement in survival has been achieved in most ID diseases (overall survival, 81.5% v 51.7%; P < .01), primarily because of a decrease in the frequency of infectious complications. In long-term survivors, disease correction is excellent, with minimal sequelae in most patients. In 22 patients who received closely matched BM (ie, from phenotypically identical related donors, matched unrelated donors, or one HLA-ag- mismatched related donors), the survival rate (45.5%) was not significantly better than among 71 recipients of BM with 2 or 3 mismatched HLA antigens (38%). In the latter group, favorable outcome was associated with younger age, with transplantation since October 1985 (47% v 25%; P < .0001), and with a diagnosis of leukocyte adhesion deficiency. The improvement in outcome was mainly because of a higher engraftment rate and a decrease in the frequency of infections, although Epstein-Barr virus-induced B-lymphocyte proliferative disorders occurred in 16 patients (mainly those with Wiskott-Aldrich syndrome), 10 of whom died. The improvement in engraftment corresponded to the introduction of treatment in vivo with anti-LFA-1 antibody to prevent rejection of T-cell-depleted grafts (74% engraftment and 45% survival in 38 treated patients versus 37.5% and 21%, respectively, in 24 untreated patients.