Ce/Ti/Zr mixed oxide thin films were prepared using sol-gel process with mole ratios from 45/5 to 5/45 of Ti/Zr and 50 of Cc and deposited by dip coating technique. Optical, electrochromic, and structural properties of such films were investigated. The thickness, refractive index, and extinction coefficient of the films were calculated through transmission and reflection measurement by an nkd spectrophotometer. The surface morphology and structural behaviors of the films were characterized by atomic force microscopy and X-ray diffraction. Cyclic voltammetry measurements also were used to study electrochromic properties of these films. The best counter electrode Ce/Ti/Zr oxide thin film is achieved for the sample with a mole ratio of 40/10 of Ti/Zr. The ratio between anodic and cathodic charge is about 0.95 for this sample with a surface roughness of 1.8 nm. (C) 2008 Elsevier B.V. All rights reserved.