A device for the preparation of thick and uniform films of ruthenium dioxide on titanium wires by the spray pyrolysis technique has been developed. The details of the apparatus, as well as the operation conditions, are described. The electrodes obtained were characterized by X-ray diffraction analysis, scanning electron microscopy and cyclic voltammetry. Their electrocatalytic activity for chlorine evolution were also evaluated, as well as their stability through an accelerated test of service life.