A simple but effective method is described for the determination of the refractive indices and thickness of light guiding optically anisotropic thin films, based on measurements of the propagation modes of the guide. The accuracy of measurements of the refractive indices and the film thicknesses can be as high as 1 x 10(-3) and 1 x 10(-4), respectively. This paper reports the computation procedure used to evaluate these parameters, together with some experimental results performed on AIN and ZnO polycrystalline oriented films and isotropic 7059 Coming glass.