Background: To determine national benchmarks and assess variability across centers, The Society of Thoracic Surgeons Congenital Heart Surgery Database was analyzed to document proportions of patients receiving intraoperative transfusion of packed red blood cells (PRBC) during open heart surgery. Methods: Index cardiopulmonary bypass operations reported in The Society of Thoracic Surgeons Congenital Heart Surgery Database (2014 to 2015) were potentially eligible for inclusion. Data from centers with more than 15% missing data for PRBC transfusion were excluded, as were individual records missing information about PRBC transfusion. The distribution of center-level PRBC transfusion rates in various clinically relevant groups was estimated by fitting a two-level logistic mixed model. Results: The study population included 22,874 index cardiopulmonary bypass operations in 81 centers. Center-level intraoperative PRBC transfusion rates stratified by age group, weight, STAT Mortality Category, and lowest core temperature were documented. For younger patients and patients undergoing higher-complexity operations, median center PRBC transfusion rates consistently approached 100%, with narrow interquartile ranges indicating little center variability. Center PRBC transfusion rates declined with increasing patient age, but with greater variability (wider interquartile ranges) across centers. Intraoperative PRBC transfusion was uncommon (median center transfusion rates <30%) in older patients (teenagers and adults) undergoing lower-complexity (STAT Mortality Category <3) operations. Conclusions: Most centers transfuse PRBCs routinely in higher-risk, younger, and smaller patients, with little variability across centers. For lower-risk operations in older and larger patients, centers are more likely to forgo intraoperative transfusions. This analysis provides national benchmarks for center-level PRBC transfusion rates during pediatric and congenital heart surgery.