Febrile children presenting to the emergency department pose unique challenges. This article highlights the importance of identifying children at particular risk of serious bacterial infection (SBI) using risk factors, red flags and appropriate investigations. Emergency clinicians must be aware of the risk factors for SBI in febrile children, including young age, ill-appearing children and those with complex comorbidities or immunodeficiency. The presence of red flags in febrile children should immediately alert concern and prompt senior clinician review. This article also discusses the appropriate use of investigations and their role in complementing clinical assessment. When discharging children home after emergency department assessment, safety netting should be undertaken to ensure parents are aware when to seek further medical opinion. The presence of a prolonged fever of 5 days or longer should alert suspicion and usually requires further investigation.