Bronchial casts were found in four children during a 2-year period at the Children's Memorial Hospital. These four children represent 0.2% of the 1,943 endoscopic cases during that time. Thirty other cases of bronchial casts have been reported previously in children 9 years of age or younger, only 12 of which were not associated with cystic fibrosis. Casts may be a complication of many diseases; cystic fibrosis, asthma, bronchitis, allergic bronchopulmonary aspergillosis, and bronchocentric granulomatosis are the most common. With the exception of cystic fibrosis, these diseases may all have an allergic pulmonary reaction as the underlying cause. In all four cases reported here, the diagnosis was made at endoscopy because the clinical picture is not dissimilar from that of bronchial foreign bodies. Management includes endoscopic removal of the cast, chest physical therapy with nebulized acetylcysteine, and an evaluation to determine the underlying condition.