In the preparation of copper selenide thin films using chemical bath deposition (CBD) technique, it is observed that the pH of the final reacting mixture is the major factor controlling the composition of the film. Thin films of cubic Cu-2-Se-x and tetragonal Cu3Se2, of band gaps 2.20 and 2.83 eV, respectively, have been prepared using the CBD technique by adjusting the bath parameters like pH, temperature and the ratio between copper and selenium atoms in the reaction bath. X-ray diffraction analysis is used as the major tool for identification of these phases. The results have been cofirmed using XPS, ICP and absorption studies.