A critical parameter in Plasma Electrolytic Oxidation (PEO) is the applied current composed of electronic current caused by sparking and ionic current caused by diffusion of electrolyte ions into the oxide. A wide spectrum of current densities was applied on pure titanium to investigate the PEO mechanism. The growth process and oxide characteristics were investigated by studying the ionic/electronic current contributions during the PEO stages. The contribution of electronic current was found to dominate at low current densities (30 and 40 mA/cm(2)). The large number of plasma discharges at this condition increases the porosity and coating surface roughness. These discharges provide enough energy to raise the temperature facilitating formation of both stable rutile and metastable anatase. By increasing the current density, the incorporation of ionic current increases resulting in the formation of dense anatase coatings. The highest growth rates achieved at a balance between ionic and electronic charges. HRTEM showed that all coatings are composed of a top amorphous layer produced from electrolyte quenching and an inner layer consisting of a mixture of nanocrystalline and amorphous regions and pores. The interlayer forming at the substrate/coating interface was found to play a key role in the growth mechanism during PEO processing.