This is to report on the studies of the formation of hydrogen peroxide by the liquid phase oxidation of various secondary alcohols with molecular oxygen. Kinetic studies have been made especially in the region of large conversion of alcohols.The reaction conditions in which the chemical reaction is rate-determining were easily maintained by controlling the pressure and space velocity of oxygen. Hydrogen peroxide solution of as high as 13wt% in concentration was easily obtained.Under these conditions the following rate equation was found to be adequate.d[H2O2]/dt=kp(ki[H2O2]/kt)1/2([A]0-[H2O2])-ki[H2O2]Over-all activation energies of the formation of hydrogen peroxide from isopropanol and secondary butanol are 11.3 and 33.2kcal/mol respectively.