The effects of r.f. bias and nitrogen flow on the microstructure and mechanical properties of TiAlN films were investigated. The preferred orientations, grain size, density, adhesive strength and hardness were substantially affected by substrate bias and nitrogen flow rate. The optimized wear resistance occurred 6 ml min(-1) higher than the critical N-2 flow rate at which a stoichiometric composition could be obtained. This could be related to different kinetics of nitridation of Ti and Al.