A user interface method and apparatus is described for use with a defibrillator (100) such as an automated external defibrillator (AED). The user interface comprises a plurality of layered user interface components which become available to the operator of the defibrillator (100) as they become necessary or appropriate during the operation of the defibrillator (100) and treatment of the patient. In one embodiment, the layered user interface components comprise an on/off actuator (108), a lid (104), an electrode package (120) containing defibrillation electrodes (142, 144), and a shock key (170), as well as accompanying visual and aural instructions for operating the defibrillator (100) and for treating the patient.