To investigate the degree and the type of inflammation in the bronchial mucosa in patients with Sjögren's syndrome, we examined lobar bronchial biopsies obtained from 10 patients with Sjögren's syndrome (six with primary and four with secondary) and eight control subjects. Histochemistry with hematoxylin-eosin was performed both to identify the number of mononuclear cells and eosinophils and to measure the thickness of the basement membrane. Immunohistochemistry was performed to identify neutrophils (neutrophil-elastase), macrophages (CD68), and T-lymphocyte subpopulations (CD4 and CD8) in the submucosa. Subjects with Sjögren's syndrome presented a greater number of CD4-positive T-lymphocytes than did the normal control subjects (p = 0.0129). Instead, eosinophils, neutrophils, macrophages, CD8 positive T-lymphocytes, and basement membrane thickness were similar in the two groups. There were no differences in cell counts between patients with primary and those with secondary Sjögren's syndrome and between symptomatic and asymptomatic patients. No correlation was found between cell counts, symptoms, lung volumes, and disease duration. This study has shown that patients with Sjögren's syndrome have an increased number of CD4 positive T-lymphocytes in the bronchial mucosa outside of the bronchial glands, supporting the concept that, in the airways, Sjögren's syndrome involves also extraglandular tissues.