Au/Pt/Ag trimetallic nanoparticles (TNPs) of 1.5 nm in diameter were synthesized by reduction of the corresponding ions with rapid injection of NaBH4, and characterized by UV-vis, TEM and line EDS in HR-STEM. The catalytic activity for aerobic glucose oxidation of the TNPs is several times higher than that of Au NPs with nearly the same particle size. The alloy structured TNPs have the highest turnover frequency value for aerobic glucose oxidation among dispersed metal nanoparticles (NPs) ever reported. (C) 2011 Elsevier B.V. All rights reserved.