Multilayered TiAlSiN/CrAlYN films were synthesized on cemented carbide, silicon and SUS304 substrates with various periods and investigated their oxidation resistance and hardness. The multilayer period between 5.6. nm and 23.2. nm was obtained by controlling the rotation speed of the substrates. X-ray diffraction patterns showed that the TiAlSiN/CrAlYN multilayer films after annealed at 1000. °C for 1. h retained the nitride structure and no peaks indicating metal oxide were observed for the films. Using the glow discharge optical emission spectrometry depth profiling method, an oxidation peak was only observed around the film surface. Hardness of TiAlSiN/CrAlYN multilayer films was measured using a conventional micro-Vickers hardness tester and the result showed that it changed depending on the multilayer period. That is, the film with a period of 8.7. nm exhibited the highest hardness with 37.1. GPa, which was higher than the value calculated based on the rule of mixtures of TiAlSiN monolayer and CrAlYN monolayer. © 2012 Elsevier B.V.