Indium tin oxide (ITO) coatings of glass substrates were etched with hydrochloric acid in order to obtain different root-mean-square roughness (R-ITO) on its surface. The effect of R-ITO on the morphology, structural and optical properties of CdS films deposited was investigated. Polycrystalline cadmium sulfide thin films were deposited on ITO/glass substrates by chemical-bath deposition (CBD) at 358 K, and studied by atomic force microscopy (AFM). Roughness of CdS films (R-CdS) showed a nearly linear increase with R-ITO. The thickness of CdS films was investigated by Auger Electron Spectroscopy (AES) and showed an increment with R-CdS. X-ray diffraction results showed that CdS films have a cubic zincblende structure with a(lll) preferred orientation. The measured residual strain of the CdS films showed an initial increse with R-ITO reaching a maximum point at 15 +/- 2 nm, and after that exhibited a decreasing dependence. The optical band gap E-o of the CdS films obtained from transmittance measurements did not depend on R-ITO.