In this paper, we report the preparation and characterization of Cu-In-S thin films on stainless steel prepared by electrodeposition technique. The electrolytic bath used for preparation of the thin films consists of metal salts dissolved in a buffer solution. This buffer solution can control the formation and composition of thin films. In order to get adequate crystalline of CuInS2 thin films, the as deposited films were annealed in N-2-atmosphere. Samples were characterized using X-ray diffraction (XRD), electron probe micro-analysis (EPMA), and scanning electron microscopy (SEM). The band-gap value of the material was estimated using optical transmittance and reflectance data on thin films deposited on commercial glass/indium tin oxide (ITO) substrates. It was found that the band-gap of the films is close to 1.5 eV. (c) 2005 Elsevier B.V. All rights reserved.