There is disclosed a process for regenerating a deactivated catalyst containing a zeolite and a noble metal of group VIII of the Periodic Table supported thereon which comprises subjecting the deactivated catalyst to decoking treatment under reductive or oxidative condition and subsequently to contact treatment with a solution containing a halogen or a halogen-containing compound and thereafter calcining the deactivated catalyst. According to the above process, the catalytic activity of a deactivated catalyst is restored to the level comparable to that of a fresh catalyst by the use of an inexpensive regenerating agent and simplified steps. Thus, the regeneration process is expected to find effective use in petroleum refinery, petrochemical industry, etc.