BACKGROUND Patients with primary biliary cirrhosis (PBC) may have coincidental sicca syndrome (SS). The frequencies of SS and the occurrence of the Sjögren's-associated anti-Ro and -La antibodies in PBC patients have been reported at widely varying prevalences. This study investigated whether distinctive serologic characteristics are associated with SS in PBC. METHODS Forty PBC patients and thirty patients with other types of liver cirrhosis were tested for SS and associated autoantibodies (ANA, AMA 2, anti-Ro, anti-La, anti-U1RNP-A, -C, -68 kD, and rheumatoid factors). RESULTS Fourteen PBC patients (35%) complained of sicca symptoms, of whom 10 (25%) had a positive Schirmer-I test, and 7 (17.5%) had serologic characteristics similar to those of Sjögren's syndrome. Anti-52-kD Ro antibodies were positive in seven PBC/SS cases (p < 0.025). There was no anti-Ro positive PBC patient without SS. Three patients with PBC/SS with anti-52-kD Ro and anti-smooth-muscle antibodies developed lung fibrosis. No patient in the other cirrhosis group had SS or its characteristic autoantibody findings. CONCLUSIONS It was suggested that PBC and SS are frequently associated. Anti-52-kD Ro antibodies seem to be a characteristic serologic finding for SS in PBC, suggesting their pathogenic role in autoimmune sialadenitis.