Viral infection has been suggested as a possible cause of Sjögren's syndrome. After we had noted Sjögren's syndrome in several patients infected with hepatitis C virus (HCV), we set up a prospective study to investigate the association of Sjögren's syndrome and HCV liver disease. We studied 10 patients with primary Sjögren's syndrome and observed four with HCV infection. A striking association between HCV infection and Sjögren's syndrome was found; however, a direct link could not be proved.