To identify which clinical findings serve to differentiate acute epiglottitis from laryngotracheitis and also to evaluate the role of direct inspection of the epiglottis in the evaluation of children initially thought to have laryngotracheitis, we prospectively evaluated 155 children presenting to the emergency room with acute stridor. Three of the findings on physical examination were associated with epiglottitis: absence of spontaneous cough, drooling, and agitation. The diagnosis assigned prior to inspection of the epiglottis was incorrect in two of six patients with epiglottitis and in three of 149 patients with laryngotracheitis. The diagnosis made after inspection was correct in all 155 patients. Minor complications of inspection were seen in seven patients with laryngotracheitis. No complications were seen in the children with epiglottitis. We conclude that drooling, agitation, and absence of cough are predictors of epiglottitis, but clinical findings alone cannot exclude epiglottitis in every child who appears to have laryngotracheitis. When laryngotracheitis is the suspected diagnosis, inspection of the epiglottis by a pediatrician in a hospital emergency room is an effective aid to the evaluation of the child with acute stridor.