Hydrotalcite-supported gold nanoparticles (Au/HT) were synthesized by deposition precipitation using NH3 and successive calcination at various temperatures. Gold nanoparticles of less than 5 nm with narrow size distribution were deposited onto hydrotalcite surfaces, which were determined by TEM measurements. Au L-III-edge XANES spectra clearly indicated that calcination at temperatures higher than 373 K leads to the generation of metallic Au which is the catalytically active site for selective glycerol oxidation to glycolic acid in water with molecular oxygen under mild reaction conditions.