The redispersion of platinum on -Al₂O₃, SiO₂ and TiO₂ is experimentally studied by means of hydrogen chemisorption, XRD, TEM, and cyclohexene hydrogenation. The increase in dispersion following treatment in oxygen below 600℃ occurs only for Pt/ -Al₂O₃. For Pt/TiO₂, only the presence of chloride during oxidation brings about a significant redispersion. For Pt/SiO₂, redispersion does not occur under any condition. Redispersion can occur only in the presence of platinum oxide which can be stabilized by forming a complex with the support. The methods for determining whether or not redispersion will occur for any system and the conditions needed for redispersion are discussed.