Tracheal bronchus is a common anomaly that occurs in approximately 2% of people. Two children with multiple medical problems which led to endotracheal intubation are described. The hospital course for each child was complicated by persistent right upper lobe atelectasis. The presence of a tracheal bronchus was not recognized in either case initially; identification of this anatomic variant allowed appropriate changes in airway management. The potential for tracheal bronchus to cause, or be associated with, localized pulmonary problems is reviewed. The diagnosis of tracheal bronchus should be considered early in the course of intubated patients with right upper lobe complications.