CuO/CeO2 catalysts were prepared by the Pechini method and applied in the CO preferential oxidation (CO-PROX). The CuO content effects on the catalysts and the presence of H2O and CO2 in the reaction stream on the catalytic performance were investigated. The catalyst with 1.0 wt.% CuO presented the highest conversion and selectivity in the COPROX in the temperature range 100-250 degrees C. It was observed that the catalytic system is sensitive to the dispersion of the active phase and, independently of the copper content, the high activity of the CuO/CeO2 catalysts is closely related to the finely dispersed CuO species strongly interacting with CeO2 support. In the long-term stability test under the real CO-PROX condition with 10 mol% H2O and 15 mol% CO2 in the reactant stream, about 90% CO conversion can be maintained even at low temperature (150 degrees C) with 95% selectivity.