Modelling of monochromatic plane wave propagation in anisotropic multilayer stacks is presented in the special case of uncoupled p and s polarizations. The current efficient coherent and incoherent interference methods for isotropic multilayer stack modelling are generalized to anisotropic structures within the frame of the uncoupled polarizations condition. The main advantage of the adopted approach is that the calculated quantities are directly accessible for measurement by using conventional ellipsometry in standard configuration, in contrast to generalized ellipsometry that requires special measurement configurations and complex data processing. The developed model is then applied to fitting experimental data on both roughened and polished uniaxially anisotropic sapphire slabs, measured with phase modulated spectroscopic ellipsometry in the visible and ultraviolet spectral range. (C) 2003 Elsevier B.V. All rights reserved.