We studied 149 rheumatoid arthritis (RA) patients (mean age 68.0 years; 68 men, 81 women) with pulmonary infections. The mean age at the onset of RA and the duration of RA was 57.2±15.2 years and 10.9±11.5 years, respectively. Pulmonary infections included nontuberculous mycobacteriosis in 59 patients (Mycobacterium avium complex infection, 50 cases; Mycobacterium kansasii infection, 4 cases; others, 5 cases), pneumonia in 46 patients, pulmonary tuberculosis in 28 patients, pulmonary aspergillosis in 12 patients, pulmonary cryptococcosis in 5 patients, Pneumocystis jiroveci pneumonia in 5 patients, lung abscess in 9 patients, exacerbation of bronchiectasis in 7 patients, and empyema in 4 patients. One hundred percent of patients with exacerbation of bronchiectasis, 91.7% of patients with pulmonary aspergillosis, 87% of patients with pneumonia, and 81.4% of patients with nontuberculous mycobacteriosis had underlying lung diseases. The pulmonary infections during therapy with steroids were pulmonary tuberculosis (78.6%), pneumonia (65.2%), and pulmonary aspergillosis (58.3%), while the pulmonary infections during methotrexate treatment were Pneumocystis jiroveci pneumonia (80%), pulmonary cryptococcosis (40%), and pulmonary tuberculosis (28.6%). Pulmonary infections in RA patients who were taking TNFα inhibitors included 1 patient each with nontuberculous mycobacteriosis, pneumonia, pulmonary tuberculosis, and Pneumocystis jiroveci pneumonia. Among the RA patients with lung abscess, malignancy was noted in 55.6%, and diabetes mellitus in 22.2%. Pseudomonas aeruginosa was the second-most-common cause of pneumonia and cause of all exacerbations of bronchiectasis. As well as immunosuppressive medications (steroids, methotrexate, TNFα inhibitors) and systemic comorbid diseases, underlying lung diseases could be one of the risk factor for pulmonary infections in patients with RA. The dominant risk factor for each pulmonary infection in patients with RA might be different.