Mesoporous carbon (MC)-Poly (3,4-ethylenedioxythiophene) (PEDOT) composites are synthesized using structure-directing agents and explored as catalyst supports for polymer electrolyte fuel cell (PEFC) electrodes. To this end, platinum nanoparticles are deposited onto the composite supports as also on Vulcan XC-72 carbon black from platinum salts by formaldehyde reduction. The morphologies and crystallinity of Pt/Vulcan XC-72 and various Pt/PEDOT-MC are characterized using powder X-ray diffraction and transmission electron microscopy, which suggest Pt nanoparticles to be uniformly dispersed onto the supports. The durability of MC-PEDOT-supported catalysts in PEFCs is attributed to enhanced corrosion-resistance of MC. Indeed, the non-destructive functionalization of MC with conducting polymer makes them promising catalyst-supports for PEFCs. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3568004] All rights reserved.