Gas phase conversion of ethanol-water mixtures on copper-based catalysts leads to a significant yield of acetone. Copper catalysts containing lanthanum oxide stabilized with zirconia, in the form of the so-called La2Zr2O7 pyrochlore compound, exhibit the best performance for the selective conversion of ethanol into acetone with yields of 96% of the stoichiometric amount at 400 degrees C. Acid-base properties of the pyrochlore in addition to its higher specific surface area and copper dispersion can explain the better catalytic behavior in comparison to the other tested copper catalysts. The most plausible reaction mechanism involves ethanol dehydrogenation to acetaldehyde followed by oxidation to acetic acid and further ketonisation to yield acetone.