The surface reduction and oxidation of nanocrystalline CeO2 and CuO/CeO2 was investigated by temperature-programmed reduction (TPR) and isothermal/temperature-programmed oxidation (TPO) measurements. Samples with Cu concentrations in the range of 5-20% were prepared by homogeneous precipitation and characterized with regard to their composition, structure, and specific surface area. The quantitative analysis of H-2 TPR measurements of the mixed oxides indicated that (i) the majority of the copper component was completely reduced at temperatures below 473 K and (ii) chemisorption of hydrogen occurred at T = 375 K, catalyzed by the copper oxide. The reoxidation of the samples with N2O could also be separated into two partial reactions: (i) a reaction of N2O with adsorbed hydrogen at room temperature and (ii) the oxidation of the reduced copper component between 343 and 573 K. Annealing of Cu0.08Ce0.92O2-x at temperatures above 1073 K resulted in the precipitation of a copper oxide phase, as was evident from X-ray diffraction (XRD). Changes in the morphology of the copper component, induced by high-temperature annealing, had a significant effect on the N2O TPO profile even after annealing at temperatures below 1073 K, where XRD was not sensitive.