Plastic bronchitis is a rare disorder characterized by the formation of extensive, obstructing endobronchial casts. It is associated with asthma and complex cardiac defects such as those requiring the Fontan procedure. The treatment of plastic bronchitis comprises conventional therapy involving spontaneous expectoration and bronchoscopic removal and specific therapy with several new drugs. Herein, we describe the cases of 2 patients diagnosed with plastic bronchitis accompanied with a different underlying disease, which were treated with inhaled corticosteroid and low-dose oral clarithromycin.