The electrochemical oxidation of propyl gallate (PG) in various surfactant solutions (AOT, Triton X-100 and CTAB) and microemulsions stabilised by the anionic surfactant SDS was investigated using cyclic voltammetry. This method has been widely applied to determine the role of microenvironment on antioxidative properties of natural and synthetic substances used to protect food and other products against oxidation. In general, the addition of surface-active agents to the system makes the oxidation of propyl gallate more difficult. The peak potential is shifted to more positive values due to the interaction of the electroactive substance with the surfactant structures at the electrode and with micelles in the bulk solution. In microemulsions the oxidation process is even more difficult than in the surfactant containing solutions. The oxidation potential increases significantly when the O/W microemulsion converts to W/O microemulsion through the bicontinuous phase.