A method of analyzing the process of oxygen evolution on both RuO2 and PTFE-modified RuO2 electrodes has been developed. The method is based on the use of oxygen reduction to analyze the removal of oxygen from the electrode surface. Oxygen evolution on the electrodes is determined by a kinetic process on the electrode surface. This process depends on the rates of oxygen bubble collection, oxygen bubble escape and oxygen dissolution, which are related to the hydrophobicity of the electrode surface. The role of PTFE in oxygen evolution is also discussed.