The CeO2-ZrO2 mixed oxides are used as automotive catalyst support due to their capacity to storage and to release oxygen in lean and rich conditions, respectively, in order to assist redox reactions that minimize the emission of pollutants caused by fuel incomplete combustion. In this present work, the CeO2- ZrO2 mixed oxides had been prepared by the coprecipitation method using as precursor salts the ZrO(NO3)2 and the (NH4)2Ce(NO3)6 or the Ce(NO3)3 with the purpose of observing the influence of the cerium precursor salt in the CeO2-ZrO2 system. Moreover, the effect of some preparation conditions like drying, thermal aging, pH control and aging along precipitation was investigated. The results show that the most significant variable in the coprecipitation preparation of the CeO2-ZrO2 mixed oxides is the cerium salt precursor. There were formation of solid solutions in all samples prepared from the cerium IV precursor, while in the case of the samples prepared from the cerium III precursor, it was observed formation of two segregated phases, c-CeO2 and ZrO2. In addition, one concluded that the reduction of the obtained material does not only occur in the surface, but also in the bulk. The solid solution materials are the ones that present the best oxygen storage capacity what is very important for the use in the automotives catalysts. The thermal aging of the catalyst showed that there are a sintering due to the high temperature and a segregation of the solid solution when the material was submitted to the used aging conditions.