The thin films of cadmium indium selenide (CdIn2Se4) have been deposited onto amorphous glass substrates using simple and low cost spray pyrolysis technique. The aqueous solutions containing precursors of Cd, In and Se have been used to obtain good quality deposits at different substrate temperatures. The preparative parameters, such as substrate temperature and concentration of precursor solution have been optimized and are found to be 280 degreesC and 0.0125 M, respectively. The films have been characterized by X-ray diffraction (XRD), optical absorption and energy dispersive analysis by X-rays (EDAX) techniques. The spray-deposited CdIn2Se4 films are polycrystalline with cubic crystal structure. The optical absorption studies reveal that the transition is direct with band gap energy E-g = 1.92 eV The EDAX studies reveal that the films obtained at substrate temperature 280 degreesC are nearly stoichiometric. (C) 2002 Elsevier Science B.V. All rights reserved.