Middle lobe syndrome - recurrent atelectasis and/or bronchiectasis involving the right middle lobe and/or lingula - has, up to now, not been reported as the pulmonary manifestation of primary Sjögren's syndrome. We describe a patient in whom lymphocytic bronchiolitis in the atelectatic lobes was proved histologically from two separate transbronchial biopsies. The atelectasis responded well to glucocorticoid treatment, suggesting that the peribronchiolar lymphocytic infiltrates may have played an important role in the development of middle lobe syndrome in this patient.