The standard treatment for patients with primary antibody deficiency is immunoglobulin (IG), but the care of these patients is complex. These guidelines, initiated by the Canadian Blood Services and the National Advisory Committee on Blood and Blood Products, have been developed to facilitate and standardize the care of these patients by the various physician specialties that are responsible for their care. A panel of national expert immunologists and methodologists developed salient clinical questions; and a systematic, expert, and bibliography literature search up to July 2008 was conducted. One thousand eighty-seven citations were retrieved, and 102 reports were used in the preparation of this guideline. The recommendations provide guidance (1) on the complexity of the treatment of these patients; (2) the established benefits of IG on morbidity and mortality; (3) dosage, routes of administration, and management of reactions; (4) the various IG formulations available; (5) vaccination of these patients; and (6) research priorities.