Xerostomia is an unsatisfactory diagnostic criterion for the salivary component of Sjögren's syndrome. 48 patients suspected of Sjögren's syndrome prospectively underwent a unique labial salivary gland biopsy procedure to determine the diagnostic usefulness of the presence of focal sialadenitis in labial salivary gland biopsy. Focal sialadenitis correlated more closely with the diagnosis of Sjögren's syndrome than symptoms of xerostomia. Focal sialadenitis in an adequate labial salivary gland specimen is an objective criterion and more disease-specific feature than symptoms of xerostomia. The salivary component of Sjögren's syndrome should be redifinded as the presence of labial salivary gland focal sialadenitis.