Direct application of the Pt/gamma-Al2O3 regeneration procedure to Pt-Ir/y-Al(2)O3 reforming catalysts is ineffective because of the high susceptibility of iridium to oxidative agglomeration. However, when the catalyst chloride level is increased above a critical level before oxygen exposure, the presence of oxygen in the chlorine redispersion step is highly advantageous. It improves the redispersion effectiveness of using a low chlorine concentration, and complete iridium. redispersion can be achieved within an hour. Here, we report a detailed kinetic study on the effect of oxygen and chlorine partial pressures on iridium. redispersion and a kinetic model successfully correlating the data.