The results of studies of the preparation, structure and electrical conductivity of ZrO2:16% Y and CeO2 thin films are presented. Dense films with grain size controlled in the region of 1-400 nm have been obtained on monocrystalline sapphire and polycrystalline Al2O3, substrates using a polymeric precursor spin coating method. The electrical conductivity of nanocrystalline thin films has been studied as a function of oxygen activity and temperature and correlated with the microstructure. Nanocrystalline specimens are characterized by enhanced electrical conductivity and different stoichiometry compared with microcrystalline material.