We examined one group of 33 patients with primary Sjögren's syndrome, one group of 17 patients with secondary Sjögren's syndrome, i.e. associated with other connective tissue diseases, and one group of 14 patients with connective tissue diseases but without Sjögren's syndrome. In each patient we obtained chest radiographs and measured lung volumes, carbon monoxide diffusing capacity and airway responsiveness to methacholine. We observed no difference in chest radiograph abnormalities, in lung volumes and in carbon monoxide diffusing capacity among the three groups. However, we found a slight but significant increase of bronchial responsiveness in patients with primary and secondary Sjögren's syndrome compared with patients with connective tissue disorders but without Sjögren's syndrome. Thus PD20FEV1 methacholine was 1.07 mg (1.2) (geometric mean and GSEM) in primary Sjögren's syndrome, 0.91 mg (1.4) in secondary Sjögren's syndrome (NS), and 2.24 mg (1.09) in patients with connective tissue diseases but without Sjögren's syndrome (t = 2.59 and t = 2.8, both p less than 0.05, vs primary and secondary Sjögren's syndrome, respectively). These results show that some patients with Sjögren's syndrome have mild bronchial hyperresponsiveness, which may be related to the specific airway abnormalities of this disease.