Abstract: A core lock assembly which is operable by two differently bitted keys is disclosed. The core lock assembly includes a shell defining a hollow portion for receiving a core which is capable of rotating to a first position under the control of a first key and to a second position under the control of a second, differently bitted key. The core lock assembly also includes a core rotation mechanism housed in the core for changing from a locked state to a first core rotatable state when the core rotation mechanism is engaged by the first key and for changing from the locked state to a second core rotatable state when the core rotation mechanism is engaged by the second key. The inner surface of the shell defines locking, first and second surface areas for cooperating with the core rotation mechanism.