Keratoconjunctivitis sicca patients diagnosed on the basis of a history, dry-eye symptoms, and definite clinical signs of keratoconjunctivitis sicca, with the associated symptoms of dry mouth and/or arthritis, had measurements of tear osmolarity, Schirmer tear test without anesthetic, stimulated parotid salivary flow, and serum analysis for the presence of autoantibodies associated with Sjogren's Syndrome. In contrast to previous studies, a lower incidence of SS-A or SS-B (1-3%), ANA (41-47%), DNA (11-16%), and RF (9-12%) serum antibodies was detected. Salivary-stimulated parotid flow was abnormally decreased in 59% of the patients. Sjogren's syndrome, as indicated by the presence of serum antibodies, appears to have a lower incidence in keratoconjunctivitis sicca than considered previously.