CuInS2 films as absorbers for solar cells were deposited by the spray pyrolysis method onto commercial ITO and TCO glasses and two different types of TiO2 and ZnO electrodes-flat and porous. Structural, morphological and electrical properties of metal oxide/CuInS2 structures have been studied. CuInS2 crystallite sizes of 6-10 nm on flat electrodes and of 20-30 nm on randomly orientated porous underlayers have been calculated. Doped large band gap oxides are found to be appropriate conductive electrodes for CuInS2 deposited with the spray process. Flat TiO2/CuInS2 and ZnO:In/ZnO/CdS/CuInS2 solar cell structures, entirely prepared by spray technique, show output characteristics of U-OC = 373 mV, j(SC) = 3.5 mA/cm(2) and U-OC = 430 mV, j(SC) = 8.1 mA/cm(2), respectively. The penetration of CuInS2 into microporous and columnar structures has been confirmed by scanning electron microscopy studies. (C) 2003 Elsevier Science B.V. All rights reserved.