A process for reducing sulfur compounds in naphtha to produce gasoline of ultra-low sulfur content, i.e., 10 30 ppm of sulfur, from a fluidized catalytic cracking reactor effluent stream, withdraws a high sulfur content sidestream of catalytically produced medium and heavy cat naphtha with an endpoint of +430.degree. F. that is fed to a side column where any thiophenic and benzothophenic compounds are catalytically reacted with hydrogen to convert them to hydrogen sulfide. The desulfurized light and mid-cut naphtha is returned to the main fractionation unit and the heavy catalytic naphtha is withdrawn as a product stream from the bottom of the side column.