Background/aim: Measles is one of the important vaccine-preventable diseases with many complications in childhood. This study presents cross-sectional seroepidemiological data, beginning from neonatal cord blood in infants to children under 6 years of age, about waning of measles antibody and tries to suggest the proper time for measles immunization.Materials and methods: A total of 564 blood samples consisting of neonatal cord blood and samples taken from infants and children at ages of 6, 9, 24-48, and 49-72 months were analyzed for measles seropositivity in a period of 6 months. Results: Measles seropositivity rate was 72.5% in 109 cord blood samples, 2.6% in 117 infants of 6 months of age, and 3.6% in 111 infants of 9 months of age. Seropositivity was determined in 118 children at 24-48 months and in 109 children at 49?72 months and was 80.5% and 66%, respectively (P = 0.001). These children were vaccinated in the 12th month. Conclusion: Though measles immunization coverage is 97% in Turkey, population immunity is somewhat lower than expected. Increases of measles cases in Europe and the refugee problem in the country could easily lead to outbreaks. Implementing the first dose of the immunization at 9 months may be an option.