CdO film has been deposited by sol-gel spin coating method on the glass substrate and then the film has been annealed at 400, 500, 600 degrees C for 1 h. Effect of annealing temperature on the structural and optical properties of the film has been investigated. The crystal structure and orientation of the as-grown and annealed CdO films have been investigated by X-ray diffraction method. Annealed CdO films are polycrystalline with (111) preferential orientation. The information on strain and grain size is obtained from the full width-at-half-maximum (FWHM) of the diffraction peaks. Texture coefficient and lattice constant have been calculated. The surface morphology of the films has been analyzed. The optical band gap value decreased with increasing the annealing temperatures. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.