The effect of preparation method on the properties of CeO2-promoted Cu/gamma-Al2O3 catalysts for CO oxidation was investigated. The effect of water vapor addition on the catalyst activities was also Studied. Experimental results show that copper catalyst activity highly depends on the preparation method. The superior activity of the catalyst can be attributed to the existence of highly dispersed copper oxide species, which strongly interact with the ceria. Addition of water vapor into the feed stream decreases the catalyst activity. The resistance of the catalysts to this deactivation is also highly dependent on the preparation method as well as on the calcination temperature. (c) 2005 Elsevier B.V. All rights reserved.