A method of synthesis of fractal films of copper sulfide is proposed. Formation of fractal films is induced by spatial patterns formed in so-called 'oxygen' oscillating chemical reaction -oxidation of ascorbic acid by air oxygen in the presence of hydrogen sulfide ions, methylene blue, and copper(II) coordination compound. The formation of the CuS film in this system is observed due to the slow reaction between copper(II) coordination compound and the hydrogen sulfide ions. A fractal dimension of CuS films correlates with the fractal dimension of chemical patterns. The electrical resistance of the fractal films and the sensitivity of Cu 2 + -selective electrodes with the fractal CuS surface to Cu 2 + ions were measured. These results are interpreted in terms of fractal dimension.