One hundred and twenty-four patients (from 120 families) diagnosed as primary immunodeficiency diseases were enrolled from five tertiary medical centers. The distribution by an update eight categories showed 45 patients (13 females/32 males; 36.3%) with "predominant antibody deficiencies," 27 patients (6/21; 21.8%) with "T- and B-cell immunodeficiency," 25 patients (9/16; 20.2%) with "congenital defects of phagocyte," 25 patients (4/21; 20.2%) with "other well-defined immunodeficiency syndromes," one boy (0.8%) with "disease in immune deregulation" (Chediak-Higashi syndrome) and another with "complement 3 deficiency." None had "defects in innate immunity" or "auto inflammatory disorders." Pseudomonas and Salmonella spp. were the two most identified microorganisms in septicemia (39.7%; 27/68 episodes). Twenty-three patients (18.5%) had mortality. Stem cell transplantation succeeded in 7 of 12 patients. In addition to nine patients with DiGerge syndrome recognized by FISH, direct sequencing identified 12 unique mutations from 20 families, reflecting distinct Taiwan geography, although a selection bias may exist.