An intelligent electronic device (IED) includes a user authentication module configured for authenticating authorized users of the IED and preventing an access by non-authorized personnel to a user-selectable portion of operational features of the IED. In exemplary embodiments, the user authentication module includes a database of information authenticating an authorized user and a sensor acquiring user-identifying information (e.g., a biometric sensor, a reader of magnetic, holographic, RFID, or smart ID cards, or a keypad). In one application, these techniques are implemented in IEDs such as electrical power and energy meters and used to control access to reset, configuration, billing, communication, and data acquisition/processing functions of the meters.