Declaration of Conformity Under MDR: What Annex IV Actually Requires

More than a signature page

The Declaration of Conformity is the manufacturer's formal legal statement that a device meets MDR requirements. It sounds straightforward — and in one sense it is. But the DoC is also an audit target, a public document, and a living record that must stay aligned with your actual conformity evidence. Teams that treat it as a one-time output at the end of the certification process tend to run into trouble when the DoC's content no longer matches the state of the device or the standards applied during its development.

Annex IV of the MDR sets out exactly what the Declaration of Conformity must contain. There are no optional fields — every element listed is required. The mandatory content is:

1. Name, registered trade name or registered trademark, and address of the manufacturer, and if applicable the Authorised Representative
2. A statement that the DoC is issued under the sole responsibility of the manufacturer
3. The Basic UDI-DI — or if no UDI has been assigned yet, sufficient information to identify the device (product and trade name, catalogue number, batch number if applicable)
4. The device name, including product name, model, and type — enough to uniquely identify what is being declared
5. The intended purpose — this should match the intended purpose statement in your technical documentation and labelling exactly
6. That the device conforms to MDR 2017/745 — and, if applicable, to any other EU legislation that the device is also subject to (e.g., Radio Equipment Directive for wireless-enabled devices)
7. References to any Common Specifications (CS) or harmonised standards applied, with the specific reference number and date — not just the standard title
8. Notified Body name, identification number, and the identifier of the certificate issued, where applicable
9. The name and function of the person authorised to sign on behalf of the manufacturer, plus their signature and date

A few of these are where audit findings cluster. The standards list is the most common problem area: manufacturers list standards that were cited in the technical documentation at development time but have since been revised or withdrawn, or they include standards that were not actually fully applied. The DoC standards list must reflect what was used — and if a standard has been superseded, you need to have made a deliberate decision about whether to transition, not just leave the old reference in the DoC.

The intended purpose wording is another area where precision matters. If the intended purpose in the DoC does not match the intended purpose in the labelling and Instructions for Use, you have a consistency problem that will surface in audit. These three locations — DoC, label, IFU — need to be kept in sync, and any change to intended purpose should trigger a review of all three simultaneously.

The Basic UDI-DI field is new relative to MDD. The Basic UDI-DI is the identifier assigned at the device model level in EUDAMED — it is not the same as the UDI-DI that appears on individual device labels. This distinction matters: the Basic UDI-DI in the DoC links the declaration to the EUDAMED device record. If EUDAMED registration is incomplete or the Basic UDI-DI has not yet been assigned, you cannot issue a final DoC. This creates a sequencing dependency that teams building their CE marking timeline need to account for.

The DoC is not a static document. It must be updated when anything material changes: the device model, the standards applied, the NB certificate number or expiry, the Authorised Representative, or the Annex IV mandatory fields themselves. In practice, a review of the DoC should be part of your standard change management process — any design change, software update affecting device function, or NB certificate renewal should trigger a DoC review. Some manufacturers set an annual DoC review as a standing QMS activity regardless of changes, which is a reasonable approach for active device families.

One detail that is easy to miss: the DoC must be available to the market surveillance authority on request and, for publicly marketed devices, to the public. Under MDR Article 19, manufacturers must draw up and keep up-to-date the Declaration of Conformity. This is not a file-it-and-forget obligation. If you are placing devices in the EU market, someone in your organisation needs to own the DoC and know the current version is accurate.