The numbers of acquired and congenital rubella infections in the United Kingdom were obtained from clinical and laboratory reports and from notifications to the National Congenital Rubella Surveillance Programme. Since 1970 the annual frequency of clinical infection has varied from 150 to 450 cases per 100,000 population and laboratory reports of infection, from 800 to 4,100 per year. The number of notified congenital rubella infections varied from 12 to 86 per year. The largest recent epidemics occurred in 1978 and 1979, with an increase in the number of congenital rubella infections during the following winters. Increased numbers of cases occurred every one to three years, with troughs of two to three years, but peaks in different localities often did not coincide. Terminations of pregnancy associated with rubella or rubella vaccination during pregnancy are reported by the Office of Population Censuses and Surveys and vary with the incidence of acquired rubella; a maximum of 830 abortions were performed in 1978 for women who acquired the disease, and from 27 to 156 were performed each year for women vaccinated just before or soon after becoming pregnant. The effect of the vaccination program is discussed in relation to the decrease in the number of young women without rubella antibody.