In the present paper, we have reported the room temperature growth of antimony sulphide (Sb2S3) thin films by chemical bath deposition and detailed characterization of these films. The films were deposited from a chemical bath containing SbCl3 and Na2S2O3 at 27 degrees C. We have analysed the structure, morphology, composition and optical properties of as deposited Sb2S3 films as well as those subjected to annealing in nitrogen atmosphere or in air. As-deposited films are amorphous to X-ray diffraction (XRD). However, the diffused rings in the electron diffraction pattern revealed the existence of nanocrystalline grains in these films. XRD analysis showed that upon annealing in nitrogen atmosphere these films transformed into polycrystalline with orthorhombic structure. Also, we have observed that during heating in air, Sb2S3 first converts into orthorhombic form and then further heating results in the formation of Sb2O3 crystallites. Optical bandgap energy of as deposited and annealed films was evaluated from UV-vis absorption spectra. The values obtained were 2.57 and 1.73eV for the as-deposited and the annealed films respectively. (c) 2007 Elsevier B.V. All rights reserved.