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Abstract: CO preferential oxidation (CO-PROX) can lead to a reduction of the CO content in the hydrogen-rich gas derived from hydrocarbon reforming down to at least 10ppmv or below, so as to enable its direct feeding to standard PEM fuel cells. Au-based catalysts supported on titania were prepared and tested as potential applications in CO-PROX operating over a temperature range compatible with PEM FCs (80–100°C). Au–TiO2 catalysts were prepared by means of two deposition–precipitation methods, varying pH (with NaOH) and some other parameters during the preparation procedure. Also the calcinations temperature was a varied parameter to evaluate the most promising catalyst. Catalyst prepared by deposition–precipitation method, using lower pH and calcined at 300°C was found to be the most suitable one for the CO-PROX at low temperature: it reduced the inlet CO concentration below 10ppmv within a temperature range of at least 60–80°C. Tests at progressively lower O-to-CO feed ratio (λ) and the same WSV value were carried out for the sake of reducing H2 consumption and improve CO-PROX selectivity. For 2%Au–TiO2 the minimum λ value, ensuring a sufficiently wide temperature range of a nearly complete CO conversion at temperatures compatible with PEM FCs operation was found to be equal to 4. Tests doubling WSV were also carried out, but a complete CO conversion was not reached. Finally, CO inlet concentration was reduced to 0.5% (possible CO outlet concentration from WGS stage); parasite RWGS reaction seemed to take place leading to worse performance. [Copyright &y& Elsevier]