Laryngomalacia is a well-recognized cause of airway obstruction and inspiratory stridor in infants. As children grow and become more active, laryngomalacia may manifest in different, unexpected ways. Otherwise healthy athletes may generate enough inspiratory force to draw the aryepiglottic folds into the endolarynx, causing a subtotal glottic obstruction. This problem may be overlooked or attributed to asthma, lack of fitness, or functional abnormalities. The purpose of this report is to review the prevalence, diagnosis, and treatment of exercise-induced laryngomalacia (EIL) in children and young adults. To study the incidence and diagnosis of this disorder, we examined 10 healthy volunteers. Fiberoptic laryngoscopy was used to videotape each subject's larynx during active exercise on a stationary bicycle. All volunteers demonstrated altered laryngeal dynamics with exercise, and 1 of the 10 volunteers developed laryngomalacia. Anatomically, it appears that the aryepiglottic fold serves as the critical point of obstruction. When symptomatic, laryngomalacia may be treated with supraglottoplasty. We have had experience with 2 EIL patients in the last 12 months who have undergone carbon dioxide laser microlaryngoscopy. Both patients benefited significantly from surgery. We conclude that EIL is underdiagnosed but responds well to treatment.