Sepsis can cause a cascade of changes that damage multiple organ systems, leading them to fail, sometimes even resulting in death. Symptoms include fever, difficulty breathing, low blood pressure, fast heart rate, and mental confusion. Using 25 clinical features attainable over the first 24 hours of hospitalization, we subtyped pediatric sepsis into four phenotypes: PedSep-A, PedSep-B, PedSep-C, and PedSep-D.