Subcutaneous IgG treatment for primary immunodeficiencies (PI) is particularly well suited for children because it does not require venous access and is mostly free of systemic adverse events (AEs). In a prospective, open-label, multicenter, single-arm, Phase III study, 18 children and five adolescents with PI were switched from previous intravenous (IVIG) or subcutaneous (SCIG) IgG treatment to receive dose-equivalent, weekly subcutaneous infusions of Hizentra(®) for 40 weeks. Mean IgG trough levels were maintained in patients previously on SCIG, or increased in those previously on IVIG, regardless of age. No serious bacterial infections were reported during the efficacy period of the study. The rates of non-serious infections were 4.77 (children) and 5.18 (adolescents) infections per patient per year. Related AEs were observed in seven children (38.9%) and two adolescents (40%). Three serious AEs and two AEs leading to discontinuation (all unrelated) were reported in children. Hizentra(®) is an effective and well-tolerated treatment for pediatric patients.