The present study was designed to assess the effect of intraperitoneal infusion of immunoglobulin (Ig) on neutrophil functions in uninfected and infected patients treated by continuous ambulatory peritoneal dialysis (CAPD). Fourteen children were included in the study. Healthy laboratory and medical personnel (n = 10) sewed as controls. Blood and peritoneal dialysate effluent (PDE) samples were obtained before and after Ig infusion. In all patients, chemotactic response of peripheral blood neutrophils (PBN) was significantly lower than in healthy controls. Peripheral blood neutrophils obtained from patients during peritonitis episodes (n = 10) showed significantly higher values compared to the values obtained from patients without peritonitis (n = 12). After the intraperitoneal infusion of Ig (100 mg/kg), chemotaxis of PBNs increased significantly in both patient groups. Chemiluminescence measures of PEN of the uninfected (n = 12) and infected patients (n = 7) were similar. They increased significantly in both groups after the Ig infusion, although they remained within the lower limits of the controls. The peritoneal neutrophils (PNs) showed significantly lower chemotactic activity in uninfected patients (n = II) than in the infected ones (n = 10). The response of PNs to the Ig infusion was also more prominent in infected patients. Immunoglobulin infusion did not increase the chemiluminescence of PNs in infected patients (n = 7); the chemoluminescence of PNs did increase after Ig infusion in uninfected patients (n = 12). These data suggest the of administration intraperitoneal Ig for prophylaxis and/or treatment of peritonitis in CAPD patients.