Background In 2019, AABB released the bulletin “Recommendations on the Use of Group O Red Blood Cells” in which the recommendations about pediatric and neonatal blood transfusions were limited. Eight U.S. pediatric hospitals sought to determine trends in pediatric group O blood use and clarify which pediatric populations receive group O blood transfusions despite a non-group O blood type. Study Design and Methods Eight U.S.-based institutions serving a pediatric population provided data from their respective Electronic Health Records. Data submitted included unit blood type, patient blood type, patient age, sex, and discharge diagnosis. If the discharge diagnosis was not available, the admitting diagnosis was substituted. GPT-4 was used to sort diagnoses into categories for analysis. Data were visualized using a series of alluvial plots, spaghetti plots, and tables. Tables were stratified on variables of interest (blood type, age, sex, diagnosis) to explore O blood type distribution among different patient populations. Results A total of 142,227 discrete transfusion events were identified, of which 52,731 recipients were non-O blood type. Overall, 35,575 transfusion events of O blood went to A, B, or AB blood type recipients (67%). Additionally, 26% of Rh(D) negative transfusion events went to recipients who were Rh(D) positive. Top diagnostic categories for receiving O blood type were cardiovascular disorders (22%) and sickle cell anemia (15%). Discussion This study highlights opportunities to address O blood supply challenges by identifying where non-O blood may be utilized safely in the vulnerable pediatric population.