The major goal of rubella immunization is the prevention of the congenital rubella syndrome. As many as 20 per cent of women in the reproductive age group in the United States continue to be susceptible to rubella despite the immunization programs currently in place. Intensified efforts are therefore needed to identify persons at risk for infection and to vaccinate them. Women who develop a rubella-like illness during pregnancy should have the diagnosis confirmed serologically because a diagnosis based on clinical criteria alone is unreliable and because of the serious implications of gestational rubella infection. The rubella virus can infect the fetus at any stage of pregnancy, but defects are rarely noted when this occurs after the 16th week of gestation. The most common abnormalities in the congenital rubella syndrome are hearing loss, mental retardation, cardiac malformations, and eye defects. Diabetes mellitus, thyroid disease, glaucoma, and other delayed manifestations of congenital rubella syndrome are common, thereby necessitating long-term followup of these patients. The detection of rubella-specific IgM antibodies in fetal blood is helpful in establishing the diagnosis prenatally and can aid in the management of pregnancies complicated by this infection. Susceptible women identified through screening during pregnancy should be immunized in the immediate postpartum or postabortion period. Although the live, attenuated rubella vaccine is contraindicated during pregnancy, pregnant women who are inadvertently immunized are not candidates for pregnancy termination because no defects consistent with congenital rubella have been reported to date in the offspring of other similarly vaccinated women.