Novel Gas Diffusion Electrodes (GDEs) for Polymer Electrolyte Membrane Fuel Cells (PEMFCs) were prepared by in situ growing Pt nanowires on carbon paper using a facile deposition method at room temperature. Pt nanowires, with a length 100-150 nm, were uniformly coated on the carbon fiber surfaces in carbon paper. This route was much simpler than the traditional method for preparing GDEs because there were no processes needed to make the ink or print the catalysis layer. Membrane Electrode Assemblies (MEAs) were made with the as-prepared GDEs and tested in a 25 cm(2) PEMFC fed by hydrogen/air. The impedance spectroscopy and polarization curve measurement showed that the as-prepared GDE possessed a lower charge transfer resistance and a higher power density than did the conventional one with ELAT(R) GDE LT120EW. The excellent performance obtained and the simple steps made the process a promising technique for preparing GDEs in PEMFCs for commercial applications. (C) 2009 Elsevier B.V. All rights reserved.