Whooping cough is a vaccine-preventable infectious diseases caused by Bordetella pertussis/parapertussis. Despite of routine immunization programs in the world, pertussis still remains endemic. Recently unvaccinated or partially immunized infants have infected with this pathogen and also increase of incidence was observed in adolescents and adults. The source of pertussis in newborns are attributed to household, especially due to the family members. Theaim of this study was to determine B.pertussis IgG antibody positivity by ELISA method in adults. Eighty-four of the total study population (39.6%) were anti-pertussis IgG positive, 128 (60.4%) were negative. The samples included in the study (n=212) were divided into three groups according to ages: 19-35 years (Group 1, n=61), 36-50 years (Group 2, n=58), 51-65 years (Group 3, n=93). Anti-pertussis IgG antibody positivity was 26.2% (n=22) in Group 1, 26.2% (n=22) in Group 2 and 47.6% (n=40) in Group 3. According to the anti-pertussis IgG positivity results, no significant difference was observed between genders. The results were obtained as absorbance values by ELISA test, then transformed into semi-quantitative values as NovaTec Test Unit (NTU). NTU positive values were between 11.01-39.4. Ninety four percent of NTU values were in the range of 11.01 to 28.01 and 6% were between 28.01 to 39.4. It was observed that seropositivity rates peaked at ages of 27, 55 and 65. The highest NTU values were observed in the age of 32 in females and in the age of 24 in males. Relatively, low seropositivity values (NT=15-20) were observed in both females and males to the age of 45 in Group 2. However a slight increase was observed in females after the age of 45. An increase (NTU >= 20) was determined in the age of 49 in males. The seropositivity rates were generally low (NT <= 20) in females in Group 3, but the highest values (NTU >= 30) were observed in 55 and 65 years of age in males in this group. The highest seropositivity (NTI >= 30) were in 55 and 65 years of age (NTI >= 30) in males and 27 years of age (NTU >= 30) in females while in 36-50 age range, it was relatively low (NTI <= 20). Routine pertussis vaccination program is not yet implemented for adults in our country. However, the causes more clearly demonstrate the need for adult pertussis vaccination since adults may be incompletely vaccinated or not vaccinated in the childhood, current vaccinations are not available in the childhood of adults, adults become more susceptible to infections as the age increases, life expectancy increases and the likelihood of encountering infections, and childhood vaccination antibodies diminish over time. According to the results of this study, a single dose of pertussis vaccine is recommended to implement for adults in our country.