In Japan, mass vaccination for diphtheria, pertussis, and/or tetanus has been mandated by the Vaccination Law since 1948. In order to evaluate the efficacy of this vaccination policy, we conducted seroepidemiological studies on pertussis, diphtheria, and tetanus among individuals aged 0 - 80 years. The pertussis toxin seropositive rates of the vaccine-eligible groups and vaccine-ineligible groups were 55.0 and 57.9%, respectively. The seropositive rate of each group for diphtheria antitoxin was 76.3 and 75.7%, respectively. The tetanus antitoxin seropositive rates were 91.7 and 10.5%, respectively, showing a significant difference between the two groups (P < 0.001). For the three diseases, variations were seen between age groups in the geometric mean antibody titers due to changes of the vaccination program. The results of this study show that natural Bordetella pertussis infection has occurred more frequently than expected. In order to establish the most appropriate vaccination program for the control of pertussis, diphtheria, and tetanus in Japan, further evaluation is necessary.