Examination of the risk factors for peritonitis appearance in patients on chronic peritoneal dialysis is on great importance for better understanding of its therapy and prevention. The aim of the study was to confirm the significance of some local defense parameters of peritoneal space and its role in peritonitis incidence. The methodology was: radial immunodifussion (IgG), nephelometry (C3), ingestion of the yeast particles (phagocytosis) and bioassays for cytokine determination. The level of termostable opsonines (IgG) was significantly lower in patients with high peritonitis incidence. Also, TNF, IL6 and IL1 activity was elevated or very high in 42.1%, 57.8% and 47.3% in the same group of patients but almost unmeasurable in patients with low peritonitis incidence. Phagocytosis by peritoneal macrophages was similar in all patients and the level of termolabile opsonines was critically low in the peritoneal fluid of all patients. The presented differences in local defense parameters may partly explain the susceptibility to infection in some patients being on chronic peritoneal dialysis.