In Indonesia, measles immunization programme had been implemented since 1982 and Indonesia had reach the Universal Child Immunization (UCI), the immunization coverage was more than 80% and it had been reached in 1991. Due to this success the measlse cases should be reduced, but the fact was, there were still outbreaks in many regions in Indonesia. And some of measles cases had been immunized before. The objective of this study was to determine the antibody titre of the children under 5 years of age, who had been measles' immunized before, lived in the measles potential and non potential outbreak regions in Kebumen District. Fifty five samples had been collected from each regions in this study. The inclusion criteria were healthy children, under 5 years old, had been measles immunized and had never got measles. The measles antibody titre was determined by neutralization test with vero cell. There was no significant difference (p=0.580, p=0.834 and p=0.996) among proportion of measles positive antibody titre, measles protective antibody titre and the GMT antibody between children who lived in the measles potential and non potential outbreak regions. There was negative measles antibody titre (titre < 8), although they had been immunized. The proportion of negative measles antibody titre was 10.9 -16.4%. There was no significant difference of the GMT antibody by sex, age groups and nutrition status. In this case booster was needed because the percentage of measles protective titre was low. It could be achieved by measles BIAS (school children immunization month) programme.and that had been implemented since 2003.