Abstract: A method of batchwise oxidatively reducing radioactive wastes mainly composed of various combustible or poorly combustible organic compounds or the mixtures thereof and containing a small amount of inorganic substances. The oxidative decomposition is carried out in an aqueous solution containing a fusion-preventive agent and a catalyst. The process allows radioactive waste to be oxidatively decomposed effectively and safely while requiring low amounts of energy thereby permitting the volume of the final wastes to be discharged and stored after the oxidative decomposition to be minimized.