The literature published over the past year on Sjögren's syndrome is reviewed, including epidemiology, genetic, environmental, and clinical features. The criteria for the classification of Sjögren's syndrome remain controversial, potentially leading to confusion in clinical practice and in research publications. Dryness of the eyes and mouth can result from either interruption of the neurovascular innervation of the glands or from any infiltrative process that affects the ability of the glands to secrete. Recent studies have demonstrated that sicca symptoms also can result from autonomic neuropathy in patients with diabetes, multiple sclerosis, or systemic lupus erythematosus. It is suggested that the term Sjögren's syndrome be used to describe one subset of patients with sicca symptoms who exhibit particular major histocompatibility complex antigens, the presence of T cell lymphoid infiltrates on glandular biopsy, and specific autoantibodies in their sera. Even using these restrictive criteria for classification, no single environmental factor has been shown as necessary or sufficient for pathogenesis. Recent studies on Epstein-Barr virus have indicated a novel deleted virus in some Chinese Sjögren's syndrome patients. Other patients with sicca symptoms and autoimmune features may have infections with HIV or hepatitis C virus.