Supported iridium-containing hydrocarbon conversion catalysts which are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are regenerated by contacting the catalyst, prior to contact with oxygen at elevated temperature, with a chlorine-containing reagent to increase the catalyst chlorine content to at least 1.0 wt. %, based on anhydrous catalyst, and thereafter contacting the catalyst with a gaseous mixture containing oxygen, a chlorine containing reagent, and water at a temperature of about 750.degree. to 1000.degree.F. for a time sufficient to burn at least a portion of the carbonaceous residues from the catalyst.