Poly(3-methylthiophene)/CeY zeolite nanocomposites (P3MT/CeY) were prepared by chemical oxidative polymerization using anhydrous FeCl 3 as the oxidizing agent. The physical and chemical properties of the prepared samples were measured using various characterization techniques, such as conductivity measurements, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Xray diffraction (XRD), thermogravimetric analysis (TGA) and carbon-sulfur analysis. The prepared P3MT/ CeY composites retained the crystalline structure of Y zeolite, which also enhanced thermostability. A 2000-fold increase in conductivity relative to a blank prepared using P3MT was observed for the composite prepared using a 3 : 1 g mL À1 ratio of CeY and P3MT.