The oxidation reaction of dibutylsulfoxide to the corresponding sulfone by dilute hydrogen peroxide is investigated over Ti-containing zeolites as catalysts; Ti-beta is more active than TS-1, as for the oxidation of sulfides under similar conditions. The kinetic parameters are determined over Ti-beta in t-butanol as solvent, and the kinetic law of the sulfoxide oxidation reaction is established. The influence of the reaction temperature and effect of the solvent are also reported.