The effect of H2O2 on adenovirus types 3 and 6, adenoassociated virus type 4, rhinoviruses 1A, 1B, and type 7, myxoviruses, influenza A and B, respiratory syncytial virus, strain Long, and coronavirus strain 229E was studied in vitro, using different H2O2 concentration and timec of exposure. H2O2 in a 3 percent concentration inactivated all the viruses under study within 1--30 min. Coronavirus and influenza viruses were found to be most sensitive. Reoviruses, adenoviruses and adenoassociated virus were relatively stable. H2O2 is a convenient means for virus inactivation.