Catalytic epoxidation of olefins

A method of epoxidation of olefins by hydrogen peroxide at a temperature between 0.degree. C. and 120.degree. C. in a liquid phase which comprises, reacting an olefin and hydrogen peroxide in the presence of a catalyst selected from boron oxide or boron oxyacid catalysts, used in an amount of 0.0001 mole to 1 mole of catalyst per mole of hydrogen peroxide, continuously eliminating water introduced with the hydrogen peroxide as well as the water formed in the course of the reaction, from the reaction mixture by distillation during the course of the reaction, and recovering the epoxidized olefin.