In 156 infants and children referred for flexible fiberoptic bronchoscopy (FFB) we examined the larynx before and after application of 2% lidocaine solution to see what effect topical anesthesia might have on laryngeal function. All patients received midazolam and nalbuphine intravenously. Using blinded, randomly re-recorded key segments of the original video recordings of bronchoscopy, we used an empirical scoring system (Table 2) to grade signs of laryngomalacia on a scale of 0 to 8 points before and after application of the lidocaine solution. This score was based on the magnitude of collapse of the arytenoids and folding of the epiglottis during inspiration. Topical lidocaine was more likely to result in an increase in signs of laryngomalacia than in a decrease in such signs (p < 0.0001). Younger patients were more likely to have signs of laryngomalacia before topical anesthesia (odds ratio, 1.83). In a group of 10 additional patients, selected for history and physical findings consistent with laryngomalacia, application of a normal saline solution had no effect on the laryngomalacia score, but application of 2% lidocaine solution to the larynx resulted in a significant increase in this score (p < 0.001). Thus, this study has clearly demonstrated that topical anesthesia in infants and children undergoing FFB exaggerates the findings commonly associated with laryngomalacia. Because overestimation of these findings might lead to unnecessary treatment, it is important to examine the larynx and contiguous structures before applying topical anesthesia.