Central and peripheral manifestations of the nervous system were evaluated in 48 Sjögren's syndrome patients. Fifty-six percent of the patients had neurological disturbances. The most common manifestations were entrapment neuropathies (19%) and polyneuropathy (15%). Electrophysiological tests gave further evidence of subclinical nervous system involvement in Sjögren's syndrome: electroencephalography (EEG) was abnormal in 48%, and visual evoked potentials (VEP) in 12% of patients tested. To find possible neuropsychiatric abnormalities, the Minnesota Multiphasic Personality Inventory was applied, and 33/43 patients were found to have psychiatric symptoms. The most frequent were depressive symptoms. In 44% of the patients there was additional evidence of extraglandular involvement or autoimmune disorders. No correlation could be found between the groups of patients with or without neurological disturbances in relation to simultaneous occurrence of associated disorders. It is suggested that nervous system involvement in Sjögren's syndrome reflects the pathogenetic consequences of Sjögren's syndrome alone, and not those of associated autoimmune diseases of extraglandular disorders.