The results of radiographic examinations and flexible fiberoptic endoscopy (FFE) of the airways were correlated in 100 pediatric patients. For the diagnosis of laryngomalacia, tracheal stenosis and tracheal granulomas. FFE proved to be more accurate than radiography. In epiglottitis and croup, the two methods were comparable. In bronchial and resulting parenchymal disease, the chest films served as the endoscopist's guide because the consequences of bronchial obstruction manifested rapidly on chest roentgenograms. FFE was particularly useful when the chest films did not reveal or lateralize a clinically suspected foreign body. FFE was not error-free; in a small number of cases, radiologic methods provided critical diagnoses, which were not arrived at by endoscopy.