Missed sepsis diagnosis can lead to increased morbidity, mortality and length of stay. Using administrative data, this retrospective study estimated the risk of potentially missed pediatric sepsis in several emergency departments. Approximately 8% of pediatric patients admitted to the hospital with sepsis experienced a treat-and-release emergency department visit within the prior 7 days. Administrative data can be helpful for hospitals in identifying cases that require detailed record review as well as evaluating the impact of sepsis alerts and bundles.