Measurements of Poisson's ratio and the Young's modulus of thin films have been problematic. In this work, evaluation of both Poisson's ratio and Young's modulus is conducted using grazing incidence X-ray diffraction combined with measurement of the induced stress. Poisson's ratio was evaluated from analysis of the X-ray diffraction data to obtain a strain-cos(2)alpha.sin(2)psi, plot. Moreover, the Young's modulus of the films could be also calculated from that plot as well as from the residual stress, which could be determined by a measurement of stress induced substrate curvature. The ternary nitride TiAlN is used as a model system for the evaluation. The films, prepared by cathodic arc plasma deposition, exhibited a strong (111) preferred orientation and a composition corresponding to Ti0.6Al0.4N. The measured Poisson's ratio and the Young's modulus of the films were 0.143 +/- 0.003 and 310 +/- 20 GPa, respectively, which are comparable to those reported in the literature. (C) 2007 Elsevier B.V. All rights reserved.