Bronchiolitis obliterans organizing pneumonia(BOOP) is a pathologic entity characterized by the formation of plugs of fibrous tissue in bronchioles and alveolar ducts. It had been described in association with several connective tissue diseases, i.e. systemic lupus erythematosus, Behcet's disease, polymyositis-dermatomyositis, polymyalgia rheumatica and Sjogren's syndrome. Recently, there were few additional reports on BOOP, anteceded by rheumatoid arthritis. We had experienced a case of 60 years old female patient who had been admitted for acute respiratory difficulty and abnormal chest roentgenographic findings. She was diagnosed as having rhematoid arthritis 20 years ago. On the course of our treatment, she did not respond to antibiotics. Moreover, no microorganism grew in the sputum and blood. Thus, the bronchoscopic biopsy was done. The patient showed a dramatic response to steroid therapy, and the pathologic findings of the bronchoscopic biopsy confirmed as BOOP. To our knowledge, this is the first reported case of BOOP anteceded by rheumatoid arthritis in Korea.