In the present paper, we have reported the chemical synthesis and characterization of polyaniline doped with tellurium. The aniline was polymerized by chemical oxidation using ammonium persulphate as an oxidant and was doped with different concentrations of tellurium. Doped PANI was characterized by using FTIR, DSC and two-probe conductivity measurement. The dc conductivity has been measured to see the effect of tellurium and its mechanism has been explained by the formation of polarons and bipolarons that move along the polymer chain, and gives rise to the electrical conductivity. The observed increase in conductivity of polyaniline is attributed due to the incorporation of Te into the PANI chain. Glass transition temperature (T-g) and enthalpy (Delta H) have been calculated from DSC measurements. FTIR spectra suggest the structural changes after incorporation of Te in polymeric chain. (c) 2005 Elsevier B.V. All rights reserved.