A series of the Au–Cu/SiO2 catalysts including low-loaded samples with an overall metal content less than 0.5 wt% was synthesized by a redox method. The catalysts were tested in the selective oxidation of ethanol to acetaldehyde. The highest catalytic activity was observed for the catalysts having the lowest metal content due to the presence of nanosized Au particles and the synergetic effect of Au–Cu2+ interaction. Unusual reduction behavior was found for the catalysts with the 0.2 wt% content of Cu. XRD, TPR, EXAFS, and STEM techniques were applied for the catalysts characterization.