Two different types of metals (Cu and Ni) and the effect of CeO2 addition to produce a CeO2ZrO2 cosupporter were investigated through the watergas shift (WGS) reaction. It was found that the WGS activity could be enhanced with CeO2 addition. At relatively high temperature, Niloaded catalysts exhibited higher CO conversion while Culoaded catalysts demonstrated better performance at low temperatures. The stability and yield of the CO2 and H2 products of the Cu catalysts were higher than those of the Ni catalysts. These results may be caused by an irreversible adsorption of CO on Ni and the reverse WGS reaction occurring on the Ni catalysts. In situ diffusereflection infrared Fourier transform spectroscopy data suggests that the WGS mechanism likely proceeded via formate species.