Primary Immunodeficiency disease (PIDD) comprise a group of disorders of immune function. Some of the most severe PIDD can be treated with hematopoietic cell transplant (HCT). Hizentra® is a 20% liquid IgG product approved for subcutaneous administration in adults and children greater than two years of age with PIDD-associated antibody deficiency. Limited information is available on use of Hizentra® in children following HCT for PIDD. A multicenter retrospective chart review demonstrated 37 infants and children (median age 70.1 [range 12.0 to 176.4] months) with PIDD treated by HCT who received Hizentra® infusions over a median duration of 31 (range 4-96) months post-transplant. The most common indication for HCT was IL2RG SCID (n=16). Thirty-two patients switched from IVIG to SCIG administration, due to one or more of the following reasons: patient/caregiver (n=17) or physician (n=12) preference, discontinuation of central venous catheter (n=16), desire for home infusion (n=12), improved IgG serum levels following lower levels on IVIG (n=10), and loss of venous access (n=8). Serious bacterial infections occurred at a rate of 0.041 per patient-year while on therapy. Weight percentile increased by a mean of 16% during the observation period, with females demonstrating the largest gains. Mild local reactions were observed in 24%; 76% had no local reactions. One serious adverse event (death from sepsis) was reported. Hizentra® was discontinued in 15 (41%) patients, most commonly due to recovery of B-cell function (n=11). These data demonstrate that Hizentra® is a safe and effective option in children who have received HCT for PIDD.