The likelihood of an epidemic of measles in 1990-92 in Israel prompted us to study the immune status against measles in a random sample of 454 recruits aged 18-19 years in order to obtain data that might be used in determining vaccination policy. This cohort had received one dose of measles vaccine at 12 months of age. The measles immunity status was studied by determination of antibody values that were measured by means of an enzyme-linked immunosorbent (ELISA) IgG antibody test. Of the recruits, 84.6% were found to have positive sera for anti-measles IgG antibodies, while 13.7% had negative sera. Eight (1.7%) subjects had borderline results. The results of this study indicate the need to administer a second dose of measles vaccine at an older age in addition to the MMR (measles, mumps, rubella) vaccine that is now given in Israel at 12 months of age. This step will help achieve the World Health Organization's target of complete eradication of measles.