The preparation of CeO 2 –ZrO 2 mixed oxides preparation was studied by evaluating the influence of several conditions. Coprecipitation was taken as the standard method and the effects brought about by the cerium salt precursor ((NH 4 ) 2 Ce(NO 3 ) 6 or Ce(NO 3 ) 3 ), the introduction of drying and aging steps as well as pH controlling upon precipitation were analyzed. The samples were characterized by X-ray diffraction, Raman spectroscopy, temperature-programmed reduction, infrared spectroscopy, oxygen storage capacity and surface area. The use of Ce(NO 3 ) 3 leads to the formation of c-CeO 2 and t-ZrO 2 mixed oxide whereas a solid solution is achieved by using (NH 4 ) 2 Ce(NO 3 ) 6 . It was observed that the cerium precursor is the most significant parameter of preparation procedure since it defines the crystalline phases and consequently the reducibility behavior of the CeO 2 –ZrO 2 system.