Structural, electrical and optical properties of polyaniline (PAni) doped Bi(2)S(3) composite thin films prepared by electrodeposition method are reported. X-ray diffraction pattern indicates its polycrystalline nature and crystallite size increases with increase in the concentration of PAni. FTIR studies reveal that the dopant PAni has affected the absorption phenomenon in the IR region of the Bi(2)S(3) thin films. The optical band gap energy is found to be 1.91 eV for as-deposited Bi(2)S(3) thin film and it decreases with increase in the concentration of PAni. The morphology of the doped films changes due to the addition of PAni. Electrical studies indicate that the conductivity increases with increase in the concentration of PAni. The conduction results from a hopping due to localized states in the temperature range 300-358 K. Above 358 K, the conduction process is explained by the traps at grain boundaries of partially depleted grains. (C) 2009 Elsevier B.V. All rights reserved.