The coprecipitation technique has been used in order to obtain zirconia-magnesia and zirconia-ceria powders with suitable purity and sinterability, respectively. To accomplish those requests, some processing variables have been systematic studied and optimized. Similar solid solutions have been prepared by the powder mixing technique for comparison purposes. Inductively coupled plasma thermal neutron activation, nitrogen adsorption/desorption thermal analyses and scanning electron microscopy techniques have been used for powder characterization Cylindrical pellets were prepared by uniaxial and cold isostatic pressing. The characterization of the sintered pellets have been carried out by impedance spectroscopy, scanning electron microscopy and X-ray diffraction techniques. Zirconia-magnesia ceramics with a high degree of purity have been obtained., in agreement with impedance spectroscopy results that show no grain boundary blocking effects. For the zirconia-ceria system, sintered pellets with 98% of the theoretical density, and 0.5 mu m average grain size have been obtained without using any comminution or special drying processes.