In this work, we report the effect of F doping on some physical properties of CdO films. Ultrasonic spray pyrolysis technique has been used to obtain the films. Thicknesses, refractive indices and extinction coefficients of the films have been determined by spectroscopic ellipsometry technique using Cauchy-Urbach model for fitting. Transmission and reflectance spectra have been taken by UV spectrophotometer, and band gap values have been determined by optical method. X-ray diffraction patterns have been used to study the structural properties such as crystallinity level, texture coefficient, crystallite size and lattice constants. Atomic force microscope images have been taken to see the effect of F doping on surface topography and roughness of CdO films. Finally, it has been concluded that both of the F doped CdO films have improved properties and are promising materials for solar cell applications. (C) 2010 Elsevier B.V. All rights reserved.