The synthesized polyaniline (PANI) is doped with different concentrations of Samarium(III) chloride (SmCl3). The electrical conductivity of doped PANI samples has been measured in the temperature range (300-400K). It has been found that dc conductivity increases with the increase of dopant concentration. Different parameters, based on the conductivity, Such as Pre-exponential factor (sigma(0)) and activation energy (Delta E) have also been calculated. These parameters exhibit information about the nature and Suitability of the dopant. Doped samples are characterized by FTIR and Photoluminescence studies, which show the interaction of dopant with PANI. Two sharp peaks of different intensities from PL spectra at 388 and 604nm have appeared in doped PANI, which might be due to the effect of SmCl3. It has been observed that SmCl3 (dopant) shows noticeable changes in the electrical and spectroscopic properties of doped PANI. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 2315-2319, 2009