Thirty-six patients with primary Sjögren's syndrome were evaluated for respiratory manifestations using clinical, roentgenologic, functional, and in five cases, histologic criteria. Twenty seven patients (75 percent) had evidence of respiratory involvement, usually occurring early in the course of the disease. Diffuse interstitial lung disease was most common (25 percent) followed by small airways disease (22 percent), desiccation of upper respiratory tract (17 percent) and large airways obstruction (8 percent). There was no patient with pleural effusion. Transbronchial lung biopsy of five patients studied revealed interstitial pathology ranging from dense lymphocytic infiltrates to interstitial fibrosis. Roentgenologic evaluation was often suggestive of interstitial lung disease but did not correlate with functional or histologic findings.