Mo-Al-N films were deposited by a dc reactive magnetron sputtering technique. The effects of N(2) partial pressure, substrate temperature, and aluminum content on the phase composition, microstructure, hardness and oxidation resistance of the films were studied. The MoAlN films as prepared are fcc Mo(2)N structure where partial Mo sites were substituted by Al, and the grain size of the crystallites increased from 8 to 30 nm when the Al concentration was increased from 6% to 33%. In the Mo(0.94)Al(0.06)N film, the hardness can reach 29 GPa, which is much higher than that in binary Mo-N systems. The oxidation resistance temperature of Mo-Al-N film with an Al content of 6% was higher than that of Mo-N films, and with further addition of Al content, the oxidation resistance temperature increased slightly. (C) 2008 Elsevier Ltd. All rights reserved.