A process for isomerizing alkyl aromatic hydrocarbons using a catalyst comprising a zeolite and a platinum group metal component is described. The zeolite comprises a new family of zeolites designated UZM-8HS which are derived from UZM-8 zeolites by treating the UZM-8 with a fluoro-silicate salt, an acid, etc. The UZM-8HS zeolites have unique x-ray diffraction patterns.