The preparation of a three-dimensional electrode suitable for the oxidation of dilute solutions of cyanide, by the electrodeposition of PbO2 on a reticulated vitreous carbon substrate is described. The electrode obtained (RVC-PbO2) 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-PbO2 electrode has been determined.