Au/CeO₂ solids were prepared by two methods: deposition-precipitation (DP) and impregnation (Imp). The prepared solids were calcined under air at 400°C. Both types of catalysts have been tested in the total oxidation of propylene, toluene, carbon monoxide, and carbon black. Au/CeO₂-DP solids were the most reactive owing to the high number of gold nanoparticles and Au⁺ species and the low concentration of Cl⁻ ions present on its surface compared to those observed in Au/CeO₂-Imp solids.