AbstractThe plasma electrolytic oxidation (PEO) process which converts the surface of magnesium alloys into a hard ceramic like topcoat has been found to be capable of providing an enhanced wear and corrosion resistance. By changing the process parameters e.g. electrolyte composition, current density, duration etc. a wide variety of coatings can be produced and adapted to applications ranging from automotive to medical. However, latter applications are still limited. The present chapter will provide a state-of-the-art overview of PEO processing for magnesium biomedical applications including processing parameters, coating compositions and properties.