Recently, Epstein-Barr virus (EBV) has gained increasing attention as a potential causative agent of Sjögren’s syndrome, which is an autoimmune disorder characterized by lymphocytic infiltration of salivary and lacrimal glands. To determine the association between Sjögren’s syndrome and EBV, we re-evaluated the salivary gland biopsies from patients previously diagnosed to have Sjögren’s syndrome. Altogether, 20 cases of Sjögren’s syndrome were reviewed from the files of the University Central Hospital since 1975. After re-evaluation of these biopsies, however, 11 patients did not fulfil the current criteria of Sjögren’s syndrome, but were diagnosed as having chronic sialadenitis. All biopsies were processed for in situ hybridization (ISH) and polymerase chain reaction (PCR) to detect EBV DNA. With ISH, all samples were negative for EBV DNA. With PCR, however, 9 biopsies proved to be positive for EBV. 3 additional positive cases were found when the amplification product was dot-blotted and hybridized with EBV DNA probe. 10 of the EBV-positive salivary gland biopsies showed the histological features of chronic sialadenitis and only 2 cases were classified as having Sjögren’s syndrome. On the basis of the present results, the association between EBV and Sjögren’s syndr