Methanol oxidation on gold nanoparticles has been studied using cyclic voltammetry in alkaline media. The onset for methanol oxidation in 0.1 M NaOH solutions is at ca. 0.3 V (RHE) and the currents reach a maximum value at 0.8 V. In 1 M NaOH solutions, oxidation currents are measured at potentials as low as 0.1 V. Although the currents are significantly smaller than the expected limiting diffusion current for methanol oxidation, oxidation currents are partially controlled by diffusion, as revealed by rotating disk experiments. This suggests that only a small fraction of the nanoparticles is active for the oxidation. It is proposed that formate is the final product of the oxidation and formaldehyde is an active intermediate in the process. (c) 2006 Elsevier Ltd. All rights reserved.