Parotid salivary lactoferrin (LF) levels were measured in 26 patients with Sjögren's syndrome (SS), 19 patients with keratoconjunctivitis sicca (KCS) and 32 normal controls, by using a radial-immunodiffusion technique. The levels of LF were higher in SS than in KCS patients (23 +/- 21, 10 +/- 10, p less than 0.03) and in SS patients than in normals (7 +/- 6 micrograms/ml, p less than 0.001). There was some relationship of the LF level to the labial salivary gland histopathology grade.