The medical devices Directive sets general requirements and requirements relating to the design and construction of medical devices. The Directive applies to all medical devices, except for active implantable medical devices. The separate active implantable medical devices Directive is applicable to them.

The Directive defines the term "medical device" as follows: appliance for alleviating the effects of a handicap or illness.

An important point of departure is that the focus is on the primary function of a product within the framework of the Directive. For example, spectacles fall under the scope of the Directive since their primary function is aimed at counteracting partial sightedness. The primary function of a pair of sunglasses is to protect against UV radiation and may have a secondary function assisting partial sightedness. Consequently, a pair of sunglasses is not a medical appliance as described by the Directive.

The medical devices Directive came into force on 1st January 1995 with a transition period until 14th June 1998. An exception has been made for clinical thermometers, which have a transition period until 30th June 2004.