PAPILLON-LEFEVRE SYNDROME (PLS) IS DESCRIBED as the association of palmar-plantar hyperkeratosis with precocious periodontal disease which results in exfoliation of primary and permanent dentitions. This study was planned to assess the chemotaxis of peripheral blood neutrophils in 7 patients (3 females and 4 males) with Papillon-Lefevre syndrome. The neutrophil chemotaxis was analyzed using the zymosan activated serum (ZAS) assay. Chemotaxis and spontaneous migration measurements were compared to those of the healthy control subjects. The peripheral blood neutrophil chemotaxis and spontaneous migration were depressed in all patients with Papillon-Lefevre syndrome. The decreased chemotaxis of peripheral blood neutrophils strongly suggests that the neutrophils may act as one of the important key determinants in the pathogenesis of severe periodontal destruction in patients with PLS.