Two cases of Papillon-LeF evre are described. Both siblings demonstrated neutrophil dysfunction and severe precocious periodontal disease. The neutrophil locomotion defect was characterized by a decreased migration toward a chemotactic factor and decreased random migration. Binding of the chemotactic factor, FMLP, to the neutrophil surface was unchanged. Both patients harbored Actinobacillus actinomycetemcomitans and showed elevated serum IgG levels. Both patients also demonstrated salivary and serum antibody to A. actinomycetemcomitans. The Papillon-LeF evre syndrome is compared with the more common localized juvenile periodontitis.