Efforts to improve the quality of Emergency Medical Services (EMS) care for adults with out-of-hospital cardiac arrest (OHCA) have led to improved survival over time. Similar improvements have not been observed for children with OHCA, who may be at increased risk for preventable adverse safety events during prehospital care. The proposed study aims to identify patient and organizational factors that are associated with adverse safety events during the EMS care of pediatric OHCA.