Human cytomegalovirus (CMV) is the most common cause of congenital and perinatal infections. Understanding the epidemiology of CMV is a key element in development of strategies for prevention of infection in premature infants. Breast-fed infants are susceptible to CMV infection from breast milk. CMV was isolated more frequently from breast milk at more than one month after delivery than from colostrum or early breast milk. CMV particle shedding into milk whey have a more important role. Cytokines in serum and milk are related to the reactivation of CMV, which occurs locally in the mammary gland of the lactating mother after delivery. Premature infants with low concentration of serum antibodies can acquire CMV infection from the fresh breast milk containing the virus. Freezing breast milk may be protective for the preterm infant until the titer of CMV antibody increases. However clinical importance of CMV infection in premature infants by breast-feeding is still unclear. This minireview focuses on recent advances in the study of CMV infection in premature infants by breastfeeding.