Benign tracheal tumors are rare and difficult to diagnose. A delay in diagnosis is common because the symptoms mimic those of bronchial asthma. We report the case of a 42-year-old woman who was treated for asthma for 2 years before a diagnosis of pleomorphic adenoma of the trachea was made. To our knowledge, only 33 patients with pleomorphic adenoma of the trachea have been reported. We treated our patient by performing circumferential segmental tracheal resection and end-to-end anastomosis. A dynamic Y-stent was implanted for tracheal stenosis soon after the operation and it was removed 2 years later. The patient is now asymptomatic and no recurrence has been detected in the 5 years since diagnosis.