A series of ceria-containing mixed oxides has been prepared and utilized as catalysts in the oxidation of acetic acid in water. The incorporation of even relatively small amounts of ZrO2 and MnOx or CuO into the fluorite lattice of CeO2 strongly enhances the redox properties of the material with a consequent promotion of the oxidation activity. The best results are obtained with the ternary mixed-oxides CeO2,-ZrO2,-CuO and CeO2-ZrO2-MnOx which benefit from a synergetic interaction between CeO2 (whose properties are already modified by the presence of Zr) and CuO or MnOx. Analysis of metal ion concentration in the effluents after reaction indicates also a high stability of the mixed-oxide catalysts under the conditions employed.