CdxZn(1-x)O (x=0, 0.59, 0.78 and 1) films have been produced by ultrasonic spray pyrolysis technique using aqueous solutions of CdCl2 H2O and ZnCl2 on the microscope glass substrate between 325 and 400 degrees C. The CdxZn(1-x)O samples have been crystallized both cubic and hexagonal structures. The optical properties of the samples were characterized by transmittance and absorption spectroscopy measurements. Transmissions of the samples have decreased with increasing x values. The optical band gap energies of the CdxZn(1-x)O samples from the absorption spectra have been calculated between 2.48 and 3.23 eV by different Zn contents. The samples were annealed at 350 and 450 degrees C. The optical band gap energy has decreased at 350 degrees C whereas it increased at 450 degrees C. (c) 2007 Elsevier B.V All rights reserved.