A methodology-is proposed for microstructural characterization of sol-gel derived epitaxial layers. Yttria stabilized zirconia deposited on (1120) cut sapphire wafer is chosen as a representative example of an epitaxial layer fabricated by sol-gel processing. High quality X-ray diffraction data has been obtained with a homemade set-up that allows to record reciprocal space maps in a small amount of time. The diffraction profiles are modeled within the kinematical theory of X-ray diffraction on the basis of microstructural parameters. The analysis of the diffraction profiles along the q(z) direction yields the average film thickness (41 nm). the thickness distribution (5 nm) as well as the vertical strain profile. A 0.2degrees mosaicity is found from line shape analysis of the diffraction profile along the q(x) direction using two orders of reflection of the same crystallographic plane family. (C) 2003 Elsevier Science B.V. All rights reserved.