The disinfection kinetics of Legionella pneumophila by hydrogen peroxide is investigated. The change in viable cell concentration with time can be well described with first-order reaction kinetics with lag time. The first-order disinfection rate constant increases with increasing hydrogen peroxide concentration and temperature. The lag time decreases with increasing hydrogen peroxide concentration and temperature. The empirical equations are presented to estimate the disinfection kinetic parameters. The results obtained in the present study are expected to be helpful for practical operation of water system such as therapeutic spa and hot-tub for disinfection of Legionella pneumophila by hydrogen peroxide.