Forty-four sequential, unselected patients with progressive systemic sclerosis (PSS) were prospectively evaluated for evidence of coexistent Sjögren's syndrome (SS). This diagnosis was established when a patient with focal lymphocytic infiltration in the labial salivary gland (LSG) biopsy, scoring greater than or equal to 2+ in Tarpley's scale, had keratoconjunctivitis sicca (KCS) (positive rose bengal test) and/or xerostomia (subjective xerostomia and decreased parotid flow rate). Ten patients had an LSG biopsy score of greater than or equal to 2+, 3 a 1+ score, 17 had mild to moderate fibrosis only and 14 had normal tissue. Nine of the 10 patients with a greater than or equal to 2+ score had SS, according to applied criteria, suggesting a 20.5% prevalence of SS in our population with PSS. On the other hand, pure fibrosis in the biopsy was felt to be secondary to PSS. Parotid gland enlargement was present in 44.4% of the patients with SS, but was extremely uncommon in the fibrosis and normal tissue groups. Subjective xerophthalmia and xerostomia, although elicited by specific questionnaire in the majority of the patients with SS, did not constitute major complaints. Serious internal manifestations, with the exception of esophageal and pulmonary involvement, were unusual in all groups. Anti-Ro (SSA) antibodies were detected in 33.3% of the patients with SS and 11.8% of those with fibrosis. Our study suggests that SS in scleroderma is relatively common and, although lacking prominent exocrine gland symptomatology, resembles primary SS in some clinical and serologic respects.