Polymorphonuclear (PMN) cell functions were evaluated in twenty-two patients with primary Sjögren's syndrome (SS) and 45 healthy controls. Adherence, phagocytosis, chemiluminescence and bactericidal ability were not significantly reduced in Sjögren's syndrome patients. Chemotaxis and chemokinesis were markedly reduced in SS patients and the results of the former test correlated well with those of the latter. These observations suggest that the decrease in PMN cell mobility is attributable both to a primary cell abnormality and a serum inhibitory effect.