Since the early 1980s, Spain has practiced mass vaccination of preschool children and selective vaccination of prepubertal girls. Estimated vaccination coverage in the province of Guipúzcoa (Basque Country) in recent years is about 95% (confirmed minimums of 89% for preschool children and 87.5% for 11 to 12 year-old girls). From the seroepidemiological study we could deduce that there was extensive circulation of wild rubella virus until recently (72-75% of unvaccinated girls 10 to 11 years-old had rubella antibody). More than 98% of the population at risk, represented in this study by 13,564 women (67% of all who bore children over a four-year period), possessed rubella antibodies. In the course of the study period the number of subjects (puerperal women and children) susceptible to infection declined. In spite of this favorable situation, the seroepidemiological study disclosed certain gaps that should be corrected to meet the targets for the European Region of the Expanded Programme on Immunization, and to achieve the goal of elimination of wild rubella virus in the area.