Nanocomposites based on intercalated conducting polypyrrole (PPy) into the galleries of inorganic aluminum-pillared Montmorillonite (Al-PMMT) clay with varying concentrations of Al-PMMT were prepared by in situ chemical polymerization. The intercalation was confirmed by X-ray diffraction pattern. Charge transport mechanism in these composites was investigated by temperature dependent direct current conductivity measurements. An increase in DC conductivity value on addition of (Al-PMMT) clay in the composites at all temperatures and a transition from three-dimensional (3D) Mott's variable range hopping (VRH) process in pristine PPy to one-dimensional (1D) Mott's VRH process in the intercalated polymer composites has been observed. This transition in charge transport mechanism of PPy from 3D VRH to 1D VRH on intercalation has been interpreted in terms of straightening and linearization of polymer chains and decrease in inter-chain interactions in the intercalated PPy. Enhancement in mechanical properties and increase in thermal stability of the nanocomposites was also observed with the increase in weight percentage of Al-PMMT in PPy-Al-PMMT composites. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012