The possibility of decreasing the platinum loading of catalyst layers in fuel cells with a polymer electrolyte membrane, retaining a sufficiently high gas permeability and enhanced electrical and proton conductivity, has been explored. Thin Pt-C catalyst layers have been formed by simultaneous sputter deposition of pyrolytic carbon (of MPG brand) and platinum on both sides of the membrane and on the surface of gas diffusion paper. The magnetron sputtering technique is very promising for the fabrication of Pt-C catalyst layers in a membrane-electrode assembly with a low platinum loading, less than 0.05 mg/cm(2). It has been shown that the main parameters determining the electronic properties of the catalyst film depend on the porosity, temperature, and stoichiometry of the catalyst layer.