This invention is related to a catalytically cracked or thermally cracked naphtha stream. The naphtha stream is contacted with a catalyst containing from about 10 to 50 wt. % of a crystalline zeolite having an average pore diameter less than about 0.7 nanometers at reaction conditions which include temperatures from about 500.degree. C. to about 650.degree. C. and a hydrocarbon partial pressure from about 10 to 40 psia. The resulting product is a high octane naphtha.