Nanocomposites based on Polyaniline Titanium dioxide (PANI-TiO 2) were prepared by in situ chemical polymerization. The structure was confirmed by X-rays diffraction studies. The interesting behavior of the XRD pattern around 10% TiO 2 content was marked as critical concentration of the dopant. The crystallite size was found to increase for PANI-TiO 2 nanocomposites. Charge transport mechanism was investigated by temperature dependent dc electrical conductivity measurements in the temperature range of 293 Ke353 K. An increase in dc conductivity was found on addition of TiO 2 at all temperatures and three dimensional variable range hopping (3D VRH) model was the most probable model of charge transport. Activation energy, density of states and hopping length were calculated and found to be influenced by TiO 2 incorporation. Structural morphology was studied by scanning electron microscopy (SEM). The granular structure and grain size increased and was confirmed by Transmission Electron Micrographs. The tensile modulus as a function of TiO 2 loading in PANI showed enhancement in mechanical properties.