A three-way model catalyst has been prepared with 0.58 wt % Pt on Ce(0.68)Zro(0.32)O(2) mixed oxide washcoated on a ceramic monolith. Conditions of the washcoating procedure, i.e., powder size distribution and acidic nature of the slurry, have been optimized. The activity on simultaneous elimination of NO, C3H6, and CO of the prepared monolithic catalyst has been determined, fresh and after submitted to mild and severe reducing- oxidizing thermal treatments. Changes in activity have been related with the role of platinum and ceria-zirconia mixed oxide in the reaction environment. The effect of aging under severe oxidation at higher temperature has also been related to the reduction of textural properties of the catalyst. The efficiency of the prepared catalyst was compared with three-way catalyst behavior of two commercial ceria-based monolithic catalysts with similar platinum contents and washcoat percentages, describing the advantages of using ceria-zirconia mixed oxides instead of CeO2/Al2O3 to improve stability and oxygen storage capacity.