Abstract Electrochemical oxidation of glucose on gold–platinum nanocomposite electrodes and platinum-modified gold electrodes was investigated with cyclic voltammetry. Gold–platinum nanoparticles were prepared by reducing aqueous solutions containing chlorauric acid and chloroplatinic acid, and the electrodes were obtained by depositing the gold–platinum nanoparticles from the colloidal solutions onto substrates. The gold–platinum nanocomposite electrodes display high electrocatalytic activity for the glucose oxidation in alkaline solution, showing 0.30–0.35 V negative shift in peak potential as compared with bare gold electrodes, and maintain stable catalytic activity in the reaction. The results of experiments indicate that both gold and platinum act as the dehydrogenation site and gold also functions to regenerate platinum from poisoned platinum. Surface modification of gold electrodes by platinum deposition also increases electrocatalytic activity of the electrodes for the glucose oxidation, showing about 0.10 V negative shift in peak potential, but a gradual decline in reactivity is observed.