Anti-human cytomegalovirus (HCMV) properties of povidone-iodine (PVP-I) were evaluated in vitro. The effect of PVP-I was evaluated by indirect immunofluorescence assay on HCMV-infected MRC-5 cells. Percentages of fluorescent cells positive for HCMV immediate early and early antigens in cultures inoculated with AD 169 treated with PVP-I at various concentrations and reaction times were compared with the number of fluorescent cells in the controls inoculated with the virus alone. PVP-I was found to exert some inhibitory effect at a concentration of 0.5% and complete inhibition at a concentration of 7.5% on the infection of MRC-5 cells by HCMV AD 169 strain. Entirely new approaches to the prevention of HCMV infections in infants are necessary. The adequate use of PVP-I as a disinfectant may reduce the transmission of HCMV.