Pt nanoparticles have been supported on different carbon materials for their use as electrocatalysts in polymeric electrolyte fuel cells. Carbon nanofibers (CNF) and ordered mesoporous carbon (CMK-3) have been studied as supports that could replace carbon black in the preparation of commercial electrocatalysts. The use of these non-conventional carbon materials allowed the determination of the influence of the support on the physicochemical properties of catalysts. Additionally, Pt catalyst supported on Vulcan XC-72R (commercial electrocatalyst support) has been prepared in order to establish a comparison. Catalysts were prepared by the incipient wetness impregnation method, and subsequently, they were reduced in a H 2 flow. Supports and catalysts were characterized by different analytical techniques in order to determine the effect of the support. Results proved that the support has a strong influence on the physicochemical properties of catalysts. These properties depended on the nature of the support and are associated with the metal–support interaction.