The mediated electrochemical oxidation (MEO) of organic acids such as EDTA and citric acid was carried out using Ag(II) as a mediator under constant current in order to develop a radioactive waste treatment process for the safe destruction of organic compounds at ambient temperature. Ultimate conversion efficienciy of 95∼97 % was obtained with EDTA and CA due to the transportation of some of organic substrates to the catholyte across the cation selective membrane during the MEO. Organic substrates remaining in the anolyte, however, could be completely destroyed to form carbon dioxide and water by the reaction with electro-generative Ag(II). With increasing temperature, slight increase in the coulombic efficiency on the MEO of EDTA and CA was observed. Relatively small effect of temperature implies that the MEO using Ag(II) as a mediator can be used effectively for the safe destruction of toxic or hazardous organic wastes at ambient temperature.