We retrospectively analyzed our results of 30 patients with three distinctive primary immunodeficiency diseases (PIDs)–severe combined immunodeficiency (SCID, n= 11), Wiskott–Aldrich syndrome (WAS, n= 11) and X-linked hyper-immunoglobulin M (IgM) syndrome (XHIM, n= 8)–who underwent hematopoietic SCT (HSCT) during the past 20 years. Until 1995, all donors were HLA-haploidentical relatives with T-cell depletion (TCD)(n= 8). Since 1996, the donors have been HLA-matched related donors (MRD)(n= 8), unrelated BM (UR-BM)(n= 7) and unrelated cord blood (UR-CB)(n= 7). Twenty-seven of 30 patients had various pre-existing infections with or without organ damages before HSCT. Conditioning regimen and GVHD prophylaxis were determined according to disease, donor and pretransplant status. Although one of eight patients transplanted with TCD is alive with full engraftment, the other seven died. On the other hand, 18 of 22 patients transplanted without TCD are alive and well, including six of eight transplanted from MRD, seven of seven from UR-BM and five of seven from UR-CB. All 19 survivors did not require Ig supplementation after HSCT. These results indicate that UR-CBT as well as UR-BMT provides good results for PID comparable to MRD-SCT, and that early diagnosis, HSCT at early stage, careful supportive therapy and monitoring for various pathogens are important for the successful HSCT.