Follicular bronchiolitis is a rare disorder, though it has been recognized as a pulmonary involvement of rheumatoid arthritis in recent years. A 57-year-old woman with rheumatoid arthritis was admitted to the hospital with persistent productive cough and breathlessness on exertion. An open lung biopsy was performed to establish a definite pathologic diagnosis of her disease, and she was diagnosed as having follicular bronchiolitis on the basis of the histopathological findings. It is essential to differentiate this disease from other bronchiolar or lymphoproliferative disorders of the lung.