Sjögren's syndrome (SS) is characterized by the presence of least 2 components of the following three: keratoconjunctivitis sicca (KCS), xerostomia and another well-defined chronic inflammatory connective tissue disease (CTD). There is generally agreement that primary SS comprises the presence of KCS and xerostomia without the presence of a CTD, and that secondary SS occurs when a CTD is present together with KCS and/or xerostomia. However, there is disagreement as to the diagnostic criteria for the salivary component of SS (xerostomia). Assessment of this component by the presence of focal sialadenitis with a focus score on labial salivary gland biopsy is considered the most important single test. However, focal sialadenitis may occur in conditions other than SS. Therefore it is preferable to assess the salivary component with other tests as well, e.g. sialometry and salivary scintigraphy. It is demonstrated that the border between a normal and an abnormal test result may vary among investigators. Because the cause of SS is unknown, it is particularly important that international agreement on the diagnostic criteria is achieved. Investigators should state clearly in their publications how they have diagnosed SS. Patients suspected of having SS should be evaluated by a team of specialists in rheumatology, ophthalmology and odontology (oral medicine).