Abstract: Objective To assess the status and clinical significance of human cytomegalovirus(HCMV)infection of breast milk and vertical transmission.Methods Specific HCMV-IgM in human whey was detected by enzyme linked immunosobent assay(ELISA);HCMV-DNA in human whey was determined by polymerase chain reaction(PCR).Separating virus of samples were made by tissue-cell culture method.Results The positive rates of HCVMV-IgM and HCMV-DNA(18.1% and 21.0%)of breast-feeding women in rural areas were significantly higher than that(8.3% and 11.2%)in urban areas.The positive rate of HCMV-DNA(20.4%)in late milk was significantly higher than that(11.5%)in colostrum.The positive rates(47.5%)of the infants fed infected breast-milk was significantly higher than that(20.0% and 17.5%)in infants fed noninfected breast-milk and bottle feeding infants.Conclusion Breast milk with HCMV infection may be an important channel of acquired HCMV infection in infants.