Aromatization of n-pentane was investigated over a nickel ion-exchanged H-ZSM-5 catalyst (Ni-ZSM-5). It was found that the Ni-ZSM-5 catalyst was highly active and selective to aromatics, being equivalent to Ga-ZSM-5 or Zn-ZSM-5. The high aromatic yield was attributed to the increase in the number of Lewis acid sites as well as the active role of Ni2+ ions for converting the olefin intermediates to aromatics.