Plastic bronchitis is an uncommon disease of children characterized by the formation of long, branching bronchial casts. Older synonyms for this condition include fibrinous bronchitis, pseudomembranous bronchitis and Hoffman's bronchitis. Bronchial casts may be a complication of many diseases such as cystic fibrosis, asthma, bronchitis, allergic bronchopulmonary aspergillosis, and bronchocentric granulomatosis. With the exception of cystic fibrosis, these diseases may all have an allergic pulmonary reaction as the underlying cause. The authors studied a case of suspected plastic bronchitis of 19 months-old boy with a sudden onset of fever and coughing. The bronchoscopic and microscopic features of the bronchial cast are reviewed, and the results of the authors experience are reported.