OBJECTIVE Primary tracheal tumors are rare, occurring in 0.2 per 100,000 persons per year. Adenoid cystic carcinoma (ACC) is the second most common histologic type of tracheal malignancy. Its clinical behavior is different from the other tracheal neoplasms and thus should be studied separately. METHODS Retrospective review of the medical records of six patients with tracheal ACC who were treated at University Hospitals of Cleveland between 1971 and 1996 and literature review. CONCLUSIONS Tracheal ACC is an indolent tumor that affects people at any age but has a peak incidence in the fifth decade. There is a nearly equal male-to-female ratio. Almost half of tracheal ACCs occur in the proximal trachea, accounting for the most common presenting symptoms: dyspnea, cough, and hoarseness. Because of the hoarseness, patients are often referred to an otolaryngologist. Complete resection provides the best chance for increased survival. Neutron beam radiotherapy holds promise for adjuvant therapy.