The preparation of a three-dimensional electrode suitable for the oxidation of dilute solutions of cyanide, by the electrodeposition of Pb02 on a reticulated vitreous carbon substrate is described. The electrode obtained (RVC-Pb02) is corrosion resistant and allows the oxidation of less than 5 p.p.m. of CN− with a faradaic yield estimated at 50%. The mass transfer coefficient for the oxidation of the potassium ferrocyanide and the specific surface area of the RVC-Pb02 electrode has been determined.