The electrochemical preparation of polypyrrole (PPY)-poly(vinyl alcohol) (PVA) conducting polymer composite films on an indium-tin oxide glass electrode from an aqueous solution containing a pyrrole monomer, a p-toluene sulfonate electrolyte, and a PVA insulating polymer is reported. The prepared PPY-PVA composite films were characterized by Fourier Transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and conductivity measurements. The FTIR study showed that the composite of PPY and PVA formed through bond formation between PVA and the p-toluene sulfonate dopant anion. The conductivity data of PPY PVA showed that with increasing PVA concentration in the pyrrole solution, the conductivity of the prepared PPY-PVA film increased Lip to a certain level due to an increase in conjugation length, and later, it decreased with further increases in the PVA concentration in the Solution due to a decrease in conjugation length. This was supported by the FTIR band intensity I-1560/I-1480. The TGA results show that the PPY-PVA polymer composite film was thermally more stable than the PPY film. A shielding effectiveness of 45.6 dB was exhibited by the PPY-PVA composite film in the microwave frequency range. (c) 2006 Wiley Periodicals, Inc.