The pulmonary manifestations of rheumatoid arthritis (RA) include bronchiolar diseases such as follicular bronchiolitis (FB) and bronchiolitis obliterans (BO). In this study, we investigated the clinical and pathologic features of FB and BO, as well as the effect of erythromycin (EM) on these diseases. The subjects included 15 RA patients with biopsy-proven bronchiolar disease (eight with FB, seven with BO). None of the patients had Sjögren's syndrome. Eleven patients (73%) had chronic sinusitis, and 14 (93%) had a chronic cough with sputum. Bacterial culture of sputum was positive in 50% and 71% of the FB and BO patients, respectively. High-resolution computed tomography (HRCT) revealed small nodular shadows in the centrilobular regions (FB and BO), patchy areas of low attenuation (BO), and peribronchial thickening (FB and BO). Eleven patients who received EM therapy showed a significant improvement of symptoms. In addition, none of the 15 patients died of the bronchiolar disease during follow-up. In conclusion, RA patients with FB or BO basically have a chronic clinical course with main complaint of productive cough, and EM may be useful for the management of these diseases.