Polypyrrole (PPy)/graphene (GR) nanocomposites were successfully prepared via in-situ polymerization of graphite oxide (GO) and pyrrole monomer followed by chemical reduction using hydrazine monohydrate. The large surface area and high aspect ratio of the in-situ generated graphene played an important role in justifying the noticeable improvements in electrical conductivity of the prepared composites via chemical reduction. X-ray photoelectron spectroscopy (XPS) analysis revealed the removal of oxygen functionality from the GO surface after reduction and the bonding structure of the reduced composites were further determined from FTIR and Raman spectroscopic analysis. For PPy/GR composite, intensity ratio between D band and G band was high (similar to 1.17), indicating an increased number of c-sp(2) domains that were formed during the reduction process. A reasonable improvement in thermal stability of the reduced composite was also observed. Transmission electron microscopy (TEM) observations indicated the dispersion of the graphene nanosheets within the PPy matrix. (C) 2010 Elsevier Ltd. All rights reserved.