Applied to cytomegalovirus, the technique of indirect hemagglutination offers a good sensitivity and reliable specificity for serological testings. Improvements in the standardization are however still required. Sero-epidemiological studies performed in different groups of children and carried out with this method led to the following results: mother-child contagium, early infection in young infants, and influence of socio-economical and ethnical factors. Studies performed on pregnant women showed that the risk of infection decreased after the first pregnancy.