MDR Article 27 and Annex VI

UDI and Basic UDI-DI under the MDR

The Unique Device Identification (UDI) system makes devices traceable across the supply chain. Manufacturers assign identifiers from a designated issuing entity, put the UDI carrier on labels and register the data in EUDAMED.

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The identifiers

Identifier	What it identifies	Where it appears
Basic UDI-DI	A device model group - the key for EUDAMED records	Declaration of conformity, certificates, technical documentation, EUDAMED; not on the label
UDI-DI	A specific model or version and packaging level	UDI carrier on the label and packaging
UDI-PI	The production unit - lot or serial number, expiry or manufacturing date	UDI carrier on the label and packaging

Identifiers are assigned under the rules of an issuing entity designated by the Commission: GS1, HIBCC, ICCBBA or IFA.

UDI carrier deadlines on labels (Article 123)

Class	UDI carrier on label from
Implantable devices and Class III	26 May 2021
Class IIa and IIb	26 May 2023
Class I	26 May 2025

For reusable devices that require direct marking on the device itself, each date applies two years later.

Getting it right

Define Basic UDI-DI groups before drafting the declaration of conformity and applying to a Notified Body
Assign a new UDI-DI when a change could lead to misidentification of the device or ambiguity in traceability
Keep UDI data in EUDAMED consistent with labels and the technical documentation

Frequently asked questions

What is the difference between Basic UDI-DI and UDI-DI?

The Basic UDI-DI identifies a device model group and is the main key in EUDAMED and on certificates; the UDI-DI identifies a specific model and packaging level and is part of the UDI carrier on the label.

Who issues UDI codes?

The manufacturer assigns them under the rules of a designated issuing entity: GS1, HIBCC, ICCBBA or IFA.

When must Class I devices carry a UDI?

From 26 May 2025; for reusable Class I devices that need direct marking, from 26 May 2027.

EUDAMED registration

Device and UDI data.

EUDAMED registration guide

Step by step.

Technical documentation

Where Basic UDI-DI appears.

Note: This guide provides general information about Regulation (EU) 2017/745 (MDR) and Regulation (EU) 2017/746 (IVDR), not legal advice. Check the consolidated text on EUR-Lex and the relevant MDCG guidance for your device. Last reviewed 30 September 2026.