In this work we investigated the influence of CuO loading and catalyst pretreatment procedure to derive an optimal CuO-CeO2 catalyst for water-gas shift (WGS) reaction, and to study in detail structure-activity relationships. Nanostructured catalyst samples prepared by co-precipitation and a 10, 15 and 20 mol% CuO content were examined by XRD, BET and TPR/TPD analyses and subjected to pulse WGS activity tests in the temperature range of 180-400 degrees C. As evaluated by TPR/TPD and N2O chemisorption analyses, with increasing CuO loading the portion of finely dispersed CuO nanoparticles decreases on behalf of larger CuO aggregates. Strong surface structure-activity dependence in WGS reaction was observed for all catalyst samples. It was established that increasing CuO content results in higher extent of CeO2 reduction, which has a positive effect on H-2 Production during the WGS reaction. Increasing calcination temperature on the other hand reduces BET surface area, induced by CuO sintering and agglomeration of CeO2 particles resulting in a negative effect on H-2 production. Distinctive WGS activity dependence on surface acidity of examined solids was observed for all CuO loadings. ((c))2008 Elsevier B.V. All rights reserved.