The method of glow-discharge polymerization was applied to deposit highly cross-linked polymer films of 100-1000 A thickness on steel, platinum, and glassy carbon electrodes. These films were characterized by electrical, electrochemical, and optical techniques and found to be stable during electrolysis in liquid solutions of both inert and redox electrolytes. Moreover, interesting correlations between the electrochemical properties of the film-covered electrodes, studied by ac and dc techniques, and the conduction properties of metal-film-metal junctions using the same films, could be established. Under suitable and well-defined preparation conditions the films possess sufficiently high conductivity that their electrocatalytic properties can be exploited.