To evaluate the need for congenital rubella syndrome prevention in our national health programme we aimed to determine the rate of anti-rubella positivity in umbilical cord blood samples 8 years after measles–rubella mass vaccination in the Islamic Republic of Iran. In a cross-sectional study we tested umbilical cord blood samples for anti-rubella IgG and IgM by ELISA in 154 deliveries at a university hospital in Tehran. Overall 72.7% of umbilical cord blood samples were positive for anti-rubella IgG and 27.3% were negative. All of the samples were negative for anti-rubella IgM. In the samples with a history of mothers’ rubella vaccination, only 87.5% were positive for anti-rubella IgG. The results suggest the need for another mass vaccination for rubella in women of child-bearing age and continuation of routine vaccination of infants, plus consideration of obligatory anti-rubella IgG testing before pregnancy in women who were not vaccinated and vaccination of women before marriage.