Sjögren's syndrome is a chronic autoimmune and rheumatic disorder. Most patients have mild to moderate complaints and this may explain the great discrepancy in prevalence found in population studies compared to studies performed in the clinic. However, there is no straightforward and simple diagnostic test for Sjögren's syndrome, although several classification criteria have been designed. Initiatives have been taken to propose a new set of classification criteria in a joint effort by research groups in Europe and USA. A large number of autoantibodies have been reported in Sjögren's syndrome where, in some cases, the antibodies are correlated with the extent and severity of disease. The finding of serum autoantibodies directed against the muscarinic M3 receptor is an important advance in understanding the pathogenesis of not only the impaired glandular function but also associated features of autonomic dysfunction in some patients. The treatment of primary Sjögren's syndrome is still mainly symptomatic.