To clarify the clinical features of pulmonary Mycobacterium avium-intracellulare complex (MAC) infection, we retrospectively evaluated clinical manifestations, laboratory data, chest and maxillary sinus computed tomographic scans and induced sputum findings in 26 with MAC infection in comparison with 104 patients with tuberculosis (TB) infection. We found that carbohydrate antigen 19-9 (CA 19-9) and immunoglobulin A (IgA) in the serum and percentage of neutrophils in the sputum were significantly higher, and sinusitis was significantly more frequent in patients with MAC compared with patients with TB. MAC infection might be more strongly associated with impaired upper and lower airway defense mechanism in comparison with TB.