Alkene oxides are produced in a continuous integrated two-step process performed in liquid phase. Step I comprises the oxidation of a secondary alcohol with molecular oxygen to generate hydrogen peroxide at moderate temperature and pressure. This reaction mixture is introduced directly to an olefinic substrate maintained in organic solvent at elevated pressure. During step II of the procedure the olefins undergo epoxidation by the hydrogen peroxide in the presence of a catalyst of titanium-impregnated, amorphous silica. The integrated process requires no intermediate purification or enrichment step and it is particularly well adapted to the production of propylene oxide.