The seroprevalence of the measles antibody in southern Taiwan 2 years after the launch of the two-dose measles elimination program was studied using serological surveillance. Sera from 868 healthy inhabitants were collected from January to December 1993. Measles IgG antibody was detected by enzyme-linked immunosorbent assay. Measles antibody was found in 82% of infants under 3 months of age, 26% of those between 4 and 9 months and 54% of those between 10 and 15 months of age. The most common reason for postponement of vaccination was due to concomitant illness during the scheduled vaccination period. The presence of measles antibody rose sharply in children over 15 months of age, reached 90% among preschool-aged children and was 93% in school-aged children. These data suggest that a high immunization coverage rate was achieved in children over 15 months of age (92%) and that a third measles immunization at age 12 is not necessary. Future strategies for measles control should aim at increasing the immunization coverage for children between 9 and 15 months of age.