Zn-x(O,S)(y) thin films have been deposited by modified chemical bath deposition method using aqueous ZnSO4 and Na2S solutions. The Zn-x(O,S)(y) films have been characterized by X-ray diffraction (XRD). energy dispersive X-ray analysis (EDAX), high resolution transmission electron micrograph (HRTEM), optical and electrical measurement techniques. The films are nanocrystalline (50-60 nm) and consist of mixed cubic and hexagonal phases of ZnS along with hexagonal ZnO. The optical bandgap of the film is estimated to be 3.30 eV. The room temperature electrical resistivity of the film is of the order 106 Q CM. (C) 2002 Elsevier Science B.V All rights reserved.