Vaccination against pertussis has been performed since 1960. Whole cell pertussis vaccine produced by Plant of Sera and Vaccines Biomed S.A. in Kraków, has been used. After vaccination has been introduced, epidemiological situation of pertussis in Poland improved, but in 90's the decrease of immunity was observed. The aim of this work was to determine pertussis immunity of children after several years from the last dose of pertussis vaccine. For comparison purposes immunity against tetanus and diphtheria was tested. Protective antibody levels were detected in 70%, 58%, and 45% children aged 6, 7, and 8, respectively. It shows that decrease of immunity may cause increasing number of pertussis in children above 5. Taking into consideration our results, it seems necessary to introduce additional dose of pertussis vaccine among children aged 5 years. The level of tetanus and diphtheria antibodies was high in all tested groups.