We reported a case of 51-year-old female immunocompetent patient with pulmonary Mycobacterium gordonae infection. The patient complained persistent cough and sputum and occasionally hemosputum. Chest radiograph and computed tomography (CT) of the lung showed bronchiectasis and small nodules in middle lobe. Bronchofiberscopy was performed twice, and bronchial washing specimen repeatedly revealed acid-fast bacilli. The organism was identified as Mycobacterium gordonae by biochemical tests and direct sequence method. She was treated with clarithromycin (400 mg/day) over 6 months and the chest CT findings showed improvement. The case was considered to be sensitive to clarithromycin in vitro drug susceptibility test. The case suggested that clarithromycin was a useful therapeutic agent to Mycobacterium gordonae infection.