The electrospinning approach is an easy and useful method to fabricate porous supports with tailored properties for the preparation of impregnated membranes with enhanced characteristics. Therein, this technique was used to obtain polyvinyl alcohol (PVA) nanofiber mats in which Nafion (R) polymer was infiltrated. These Nafion/PVA membranes were characterized in their mechanical properties, proton conductivity and fuel cell performance. Conductivity of the composite membranes was below the showed by pristine Nafion (R) due to the non-ionic conducting behaviour of the PVA phase, although the incorporation of the PVA nanofibers strongly reinforced the mechanical properties of the membranes. Measurements carried out in a single cell fed with H-2/Air confirmed the high performance exhibited by a 19 mu m thick nanofiber reinforced membrane owing to its low ionic resistance. These reasons make ultrathin (<20 mu m) Nafion/PVA composite membranes promising candidates as low cost ion-exchange membranes for fuel cell applications. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.