Polypyrrole films containing gold nanoparticles (PPy/Au) were electrosynthesized on a glassy carbon electrode. This was done by applying a constant current of 1.43 mA cm(-2) in solutions containing colloidal Au particles and pyrrole monomer. A chloroaurate medium with a citrate/tannic acid reducing/protection agent was employed for generating the An colloids. The PPy/Au films were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Also, electrochemical behaviors of the PPy/Au films were characterized by cyclic voltammetry (CV) and AC impedance measurements. Experimental results demonstrate that PPy/Au has greater conductivity and better stability than PPy. The effect of incorporated An nanoparticles in PPy matrix was studied and the mechanism was suggested. (c) 2006 Elsevier Ltd. All rights reserved.