Medical Devices are classified according to their complexity and potential risk for the patient. In accordance with the current Regulation, four risk classes were established: I, IIa, IIb and III. The intended use the manufacturer established for the device, the device invasiveness, its energy source dependence and the time duration with the human body are the elements you need to evaluate in order to define a proper risk class. Currently, a proper classification based on the above-mentioned elements should refer to Annex IX Classification Criteria of Directive 93/42/EEC and subsequent amendments and addenda.