Immunization is one of the most cost-effective interventions for child survival and well being. The World Health Organization established and recommended the “Expanded Program on Immunization” (EPI) in 1974. In its original program, six diseases were targeted to be prevented by immunization. The program was established and accelerated between 1980-1985 in Turkey. Since then, several new vaccines have been developed and various recommendations and practices have been implemented. Overall, the EPI has progressed both in the world and in Turkey. In this manuscript, the process in progression, factors affecting national programs, changes in the program and effects on disease epidemiology are mentioned.

Keywords: Expanded Program on Immunization (EPI), world, Turkey, vaccine