Proton Exchange Membrane (PEM) water electrolysis is potentially interesting for the decentralized production of hydrogen from renewable energy sources. The European Commission (EC) is actively supporting different projects within the 6th and 7th Framework Programmes. The purpose of this paper is to provide a summary of most significant scientific and technological achievements obtained at the end of the GenHyPEM project (FP6, 2005-2008), and to discuss future perspectives. Using carbon-supported platinum at the cathode for the hydrogen evolution reaction (HER) and iridium at the anode for the oxygen evolution reaction (OER), efficient membrane - electrode assemblies have been prepared and characterized using cyclic voltametry and electrochemical impedance spectroscopy. Charge densities and impedances of lab-scale PEM cells have been measured and used as references to optimize the performances of a GenHy (R) 1000 PEM water electrolyser (1 Nm(3) H(2)/h) and then to extend the production capacity up to 5 Nm(3) H(2)/h. Different non-noble electrocatalysts have been successfully tested to replace platinum at the cathode. Some current limitations and future perspectives of the technology are outlined and discussed. Copyright (C) 2010, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.