The application of CeO2 ceramics derived from sol-gel as coatings deposited on nickel, chromium, and some nickel-base superalloys to improve their oxidation behaviour at high temperatures is presented. The major factors affecting the protective properties of CeO2 coatings, related to the coating microstructure, the nature of the substrate, and oxidation parameters are discussed. On the basis of the experimental evidence, the conditions leading to the optimum performance are selected. The efficacy of sol-gel technique is compared with results obtained by CeO2 sputtering and Ce ion implantation.