The UDI is a code of alphanumeric characters that acts as the access key to information about a specific medical device on the market. The EU MDR and EU IVDR require that a UDI be assigned to all medical devices except for custom-made or investigational devices. Within the EU, the manufacturer is legally responsible to assign both Basic UDI-DI and UDI-DI to their medical devices. The detailsare provided to operators on the application and practical implementation of the UDI requirements according to the Regulation (EU) 2017/745 on medical devices (MDR) and Regulation (EU) 2017/746 on in vitro diagnostic medical devices (IVDR).