The electrochemical reduction of hydrogen peroxide on copper electrodes in a borax buffer has been studied. The effects of surface oxidation and chloride ions in the electrolyte have been investigated. Hydrogen peroxide can be electrochemically reduced on Cu(I) oxidized surfaces. In the absence of chloride, the reduction is catalysed by a redox cycle involving the Cu(I)/Cu(II) couple. In chloride-containing solutions, the surface oxides are dissolved and the reduction becomes more irreversible. There appears to be a change in the reduction mechanism at potentials more negative than -0.45 V.