Tracheal bronchus is an ectopic bronchus almost arising from the right side of the tracheal wall above the carina. The incidence of a tracheal bronchus is reported as 0.1 to 3%. We experienced a patient with tracheal bronchus that was incidentally found at induction of anesthesia. Endotracheal intubation in a patient with tracheal bronchus might cause obstruction of the tracheal bronchus, although in this case, ventilation was not impaired.