The results of testing for rubella antibodies in over 6000 sera from women of child-bearing age are reported and analysed according to pregnant state, age, country of origin and social class. There was no difference between the rubella seroprevalence rates in women who were pregnant and in those who were contemplating pregnancy in the future. Likewise, women (either pregnant or non-pregnant) who were young enough to have been offered rubella vaccine at school were not more likely to be immune to rubella than were older women. Rubella seropositivity rates were not influenced by social class but significantly higher rates were found in women born in European or Arabian than in African or Asian countries. We conclude that the national scheme for rubella immunization has not reduced the number of women susceptible to rubella entering pregnancy in this Health District and that greater attention should be paid to immunization of women of child-bearing age from African or Asian countries.