Water deficits and their associated shortages are serious problems in many areas of the world. The paper presents a multi-criteria analysis for selection of the most suitable system in Mauritania. Six scenarios, different energy sources, technologies of water desalination processes and water use and five criteria are analyzed. The multi-criteria analysis shows that the optimal solution is different for each scenario; in some cases the photovoltaic-reverse osmosis option is preferable; in others, the best option is reverse-osmosis powered by wind energy or concentrating solar parabolic. (C) 2009 Elsevier Ltd. All rights reserved.