Cubic polycrystalline zirconia ceramics stabilized with yttria are an excellent solid electrolyte used as oxygen sensor. In this work are presented and discussed the processing and microstructure characterization of cubic polycrystalline-zirconia stabilized with a concentrate of yttrium and rare earth oxides (YRE). The raw materials are of Brazilian origin. The preparation method of the powder mixtures (15 to 23 wt% YRE) was by chemical coprecipitation of the respective hydroxides with ammonia (NH4OH). The powder mixtures were calcined, isostatically pressed and sintered at 1550degreesC. Phase analyses by X-rays diffraction (XRD) were made aided by a computer program and a mathematical model for calculation of the lattice parameters. Images from scanning electron microscopy (SEM) were used to make analyses of the sintered ceramic microstructures. The results indicated that cubic polycrystalline zirconia was stabilized with 18 wt% of yttrium and rare earth oxides (YRE) mixtures and its sintered microstructure showed a high densification.