This presentation discusses the patient compatibility of medical devices. A device is said to be patient compatible if it meets the regulatory requirements of safety, functionality and is according to the Annex 1 of the European Medical Device Directive. As it is accepted that medical devices constitute a risk, the benefits of the device should outweight the risks. The risk should be minimised hence a risk management programme must be undertaken. The relevance of device encapsulation is also discussed. If some materials are not biocompatible, they must be covered or encapsulated. A case study on an intravascular ultrasound (IVUS) coronary catheter is presented.