There are data to suggest that the method of delivery modifies the immunological balance of newborn infants. In this study, an effect of maternal labor and mode of delivery on the neutrophil activity was evaluated in healthy full-term neonates. Neutrophils were obtained from cord blood of two group neonates: 14 vaginally delivered and 12 delivered by elective cesarean section without preceding labor. Neutrophil functions were studied by measuring the chemotaxis, chemiluminescence and phagocytosis activity and by investigating the expression of phagocyte receptors CD11b on neutrophils using receptor-specificMoAbs and immunofluorescence flow cytometry. Infants born by elective cesarean section had significantly higher chemiluminescence activity, chemotaxis and higher expression of CD11b receptors than those delivered vaginally. We suggest that physiological changes associated with stress during labor could explain these differences observed in neutrophil functions.