Pertussis is a life-threatening, vaccine-preventable infection. Adults who can be asymptomatic may infect infants. The aim of this study is to determine the IgG antibody levels against pertussis toxin (PT) and filamentous hemagglutinin from 6 months to a parts per thousand yen60 years in Izmir, Turkey. A cluster sample design developed by Expanded Programme on Immunization of the World Health Organization was carried out for the selection of the study population, which consisted of 399 healthy subjects. In-house ELISA was studied in Turkish Public Health Institution. Antibody levels of < 10 EU/ml, a parts per thousand yen10 EU/ml and a parts per thousand yen100 EU/ml were accepted as non-immune, immune and possible acute/recent infection, respectively. Anti-PT antibody levels were 8.5% < 10 EU/ml, 68.2% 10-100 EU/ml and 23.3% a parts per thousand yen100 EU/ml; the latter was correlated with possible acute/recent infection. Results showed that pertussis is endemic, particularly among adolescents and adults, which is a threat for infants who have not completed their primary immunization.