Even traces of CO in the hydrogen-rich gas fed to PEM-FCs can poison the platinum anode electro-catalyst and dramatically decrease the stack power. The CO selective methanation (CO-SMET) process seems to be a good alternative to the CO preferential oxidation (CO-PROX) one for PEM-FCs applications to vehicles, boats, yachts and residential co-generators, as a CO-SMET reactor is inherently easier to control than the CO-PROX one. The present paper deals with the study on complete removal of CO in H-2-rich gas stream from a reforming process through CO-SMET over Ru-based catalysts supported on Al2O3 and CeO2 carriers. All the catalysts, with Ru load of 1%, 3% and 5%, were prepared by a conventional impregnation method, using two different Ru precursors, chloride and nitrate, and their CO removal performance was determined at the powder level in a fixed bed micro reactor. The Al2O3 carrier exhibited performances better than the CeO2 one, in particular when Ru was deposited from RuCl3 precursor. The best performance was obtained with 5% Ru-Al2O3-Cl as the temperature range of complete CO conversion with acceptably low levels of CO2 methanation (<= 50% of CO molar methanation) was the widest. (C) 2010 Elsevier B.V. All rights reserved.