CdO thin films were deposited by sol-gel spin coating. The structural, morphological and optical characterizations of CdO films were performed as a function of solution molarity. The structural and morphological analyses showed that the films had a polycrystalline cubic structure and the surfaces of films consisted of nano-sized particles. The band gap values were found to be 2.74 eV, 2.67 eV, 2.62 eV, 2.59 eV and 2.17 eV for 0.05 M, 0.1 M, 0.3 M, 0.5 M and 0.7 M CdO films, respectively. This study indicates that the properties of CdO thin films could be changed with solution molarity and these films can be used in many technological applications. (C) 2014 Elsevier B.V. All rights reserved.