Conducting polymer composite films comprised of polyaniline (PANI) and single wall carbon nanotubes (SANT) was prepared by electrochemical codeposition during the electropolymerization in an aniline solution with suspending SWNT. The fabricated composite films are assessed with respect to their potential application as support materials in Pt electrocatalyst for electrochemical oxidation of methanol. The PANI/SWNT composite film incorporated with SWNT has a higher polymeric degree and lower detect density in PANI structure than PANI film. Furthermore, the incorporation of SWNT also leads to higher electrochemically accessible surface areas (S-a), electronic conductivity and easier charge-transfer at polymer/electrolyte interfaces, which make higher dispersion and utilization for deposited Pt. Therefore, the Pt particles electrodeposited on PANI/SWNT composite polymer film exhibits excellent catalytic activity and stability for the electrooxidation of methanol in comparison to Pt supported on PANI film, which reveals that the composite film is more promising for application in electrocatalyst as a support material. (c) 2005 Elsevier B.V. All rights reserved.