Plastic bronchitis is an unusual clinical scenario of unknown cause and occurs in multiple clinical settings. The disease is characterized by the development of arborizing, thick, tenacious casts of the tracheobronchial tree that results in airway obstruction. Patients with congenital heart disease who have undergone a Fontan operation are at high risk for having this problem develop. Management of this distressing situation is difficult with only palliative options being available, such as repeated bronchoscopies, inhaled heparin, tissue plasminogen activator, inhaled bronchodilators, or azithromycin. The patients with Fontan circuits have a myriad of unique complications develop, such as atrial arrhythmias, recurrent pleural effusions, chylothoraces, protein-losing enteropathy, and plastic bronchitis. High intrathoracic lymphatic pressures with nondemonstrable lympho-bronchial fistulas were believed to be the cause for the development of these recurrent bronchial casts in plastic bronchitis. Faced with recurrent plastic bronchitis resistant to medical management in 2 Fontan patients with normal Fontan pressures on cardiac catheterization, we decided to explore a surgical solution by performing a thoracic duct ligation. This resulted in complete resolution of the formation of casts in both patients, who were discharged home and remain asymptomatic on continued follow-up. Thoracic duct ligation provides a surgical cure for plastic bronchitis by decreasing intrathoracic lymphatic pressure and flow.