The study is an analysis of the optical and electrochromic properties of antireflective WO3-TiO2 thin films prepared by sol-gel method. TiO2 (1, 5, 10 and 15 mol%)-mixed WO3 thin films were deposited on ITO-coated glass and Corning glass substrates by spin process. The titanium content of the layers was determined by X-ray photoelectron spectroscopy (XPS). Effects of annealing temperature and titanium content on the electrochromic and optical properties of the WO3-TiO2 films were investigated by cyclic voltammograms with in situ monochromatic transmittance measurements. Sol-gel derived WO3-TiO2 anti-reflection coatings on glass substrates are successfully developed. Scanning electron microscope (SEM) pictures of pure WO3 and WO3-TiO2 films indicate that even small titania contents can lead to significant structural changes of tungsten oxide films. (c) 2004 Elsevier B.V. All rights reserved.