At the Finnish Student Health Service, we have measured rubella antibodies in 3 consecutive academic years--1979-80, 1980-81 and 1981-82--in 2 483 first year female students. In 1979-80, 16.4% were seronegative, the following year the figures were 10.4% and in the third year 7.4%. Among students less than or equal to 19 yr of age the seronegatives decreased from 19 to 2% in 3 yr. This decrease shows that the national rubella vaccination programme which began in 1975 has been more successful than expected. A hemolysis-in-gel (HIG) test has proved a suitable screening method and the health examination of first year students a suitable occasion to test the immunity against rubella. Seroconversion occurred in 81.4% of those vaccinated.