The selective low-temperature oxidation of CO was Studied in hydrogen-rich stream,, over Pt-Co-Ce/Al2O3 catalysts, which were prepared using the incipient to wetness co-impregnation technique. The effects of reaction temperature and feed composition on CO conversion and selectivity were investigated in a flow micro-reactor system. The 100% CO conversion was achieved over 1.4 wt% Pt-1.25 wt% Co-1.25 wt% Ce/Al-2-O-3 with significantly high selectivity at a reaction temperature of 90 degrees C using a feed composition of 1.0% CO, 1-0% O-2, 60% H-2 and He as balance at a space velocity of 24,000 cm(3)/(g h). Addition of 25% CO2 and 10% H2O into the feed increased the reaction temperature to 110 degrees C but allowed 100% CO conversion for 300 min time-on-stream. It was Concluded that this catalyst may have great potential for removing CO in the hydrogen stream from a fuel processor for fuel cell applications, considering the fact that it may operate at significantly lower temperatures and O-2/CO ratios compared to other alternatives reported in the literature. (c) 2005 Elsevier B.V. All rights reserved.