AIM: To assess Ig20Gly tolerability in pediatric patients with primary immunodeficiencies. PATIENTS & METHODS: Infusion parameters and tolerability were analyzed in pediatric patients (aged 2-5 years [n = 6], 6-11 years [n = 22] and 12-17 years [n = 22]) receiving Ig20Gly in two Phase II/III trials. RESULTS: Of 2624 Ig20Gly infusions, >99% did not require any rate reduction, interruption or discontinuation due to adverse events (AEs). Median maximum infusion rates and volumes/site were higher in patients 12-17 years of age (30 ml/h/site; 30 ml/site) versus 6-11 years (20 ml/h/site; 15 ml/site) and 2-5 years (18 ml/h/site; 14 ml/site). Rates of causally related systemic and local AEs (0.009 and 0.063 AEs/infusion) were low. CONCLUSION: Ig20Gly infused at relatively high rates and volumes was well tolerated in children.