An improved isomerization catalyst is formed by combining a Group VIII metal, lead, a pentasil zeolite, and an inorganic oxide binder in a manner such that 80-100% of the Group VIII metal and 60-100% of the lead are contained on the binder. The resulting catalyst system is particularly useful in the isomerization of aromatic hydrocarbons and is particularly effective in a process for the conversion of ethylbenzene by dealkylation while simultaneously isomerizing xylenes where the process is to be performed without substantial loss of xylenes.