A case of reinfection with the wild rubella virus in the 8th gestational week is reported. The patient had preexisting hemagglutination inhibition antibodies of low titer following immunization with rubella vaccine. Reinfection was accompanied by clinical symptoms and the presence of rubella-specific immunoglobulin M (IgM) of high titer. Following termination of pregnancy no rubella virus could be isolated from the fetal tissues and the fetal blood contained no specific IgM antibodies. These results should encourage the use of cordocentesis before decision on interruption of pregnancy.