Epitaxial thin films of ceria zirconia solid solutions were grown on yttria-stabilized zirconia (YSZ) substrates by chemical solution deposition. Characterization by X-ray diffraction, atomic force microscopy and variable angle spectroscopic ellipsometry show that high-quality, epitaxial, high density films, with a thickness in the range of 20-27 nm were obtained. Compositional dependence of the film optical constants (n and k) was determined from ellipsometry measurements. It was found that the optical properties for the mixed-oxide films smoothly vary between the values for the pure oxides and are best described by means of a Tauc-Lorentz (TL) model. Moreover, we found that the parameters of the TL model have a linear dependence on the cerium concentration. The obtained results can serve as a database for the thickness, composition and porosity characterization of CexZr1-xO2 thin films. (C) 2012 Elsevier E.V. All rights reserved.