A modified chemical bath deposition method is used to deposit bismuth sulphide (Bi2S3) thin films of thickness about 0.14 mum under optimized deposition conditions. The films are annealed at 200 degreesC for 2h in air. It is found that deposited films turn from amorphous to polycrystalline after annealing. The microstructural, optical and electrical properties of annealed films are studied. The optical band gap is estimated to be 1.78 eV. The electrical resistivity is of the order of 10(4) Omega -cm.