--- title: "Article 34 — Communication of a personal data breach to the data subject" type: regulation legal_status: in_force source: "https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02016R0679-20160504" source_retrieved: 2026-09-28 shortTitle: "Article 34 — Communication of a personal data breach to the data subject" instrument_type: level1_regulation authority: Commission binding: true binding_character: binding mica_level2: false legal_basis: "Regulation (EU) 2016/679" instrument: gdpr celex: "32016R0679" regulation: GDPR regulation-full: "Regulation (EU) 2016/679" article: 34 status: in_force object_id: eu.gdpr.legal_text.article.34 text_version: "Consolidated version of 4 May 2016" source_url: "https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02016R0679-20160504" check_status: matched verified: true last_checked: 2026-10-26 --- *In force · Consolidated version of 4 May 2016 · Checked against EUR-Lex on 26 Oct 2026 · [Official source](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02016R0679-20160504)* 1. When the [personal data breach](https://www.headlesslaw.com/definitions/gdpr/personal-data-breach) is likely to result in a high risk to the rights and freedoms of natural persons, the [controller](https://www.headlesslaw.com/definitions/gdpr/controller) shall communicate the personal data breach to the data subject without undue delay. 2. The communication to the data subject referred to in paragraph 1 of this Article shall describe in clear and plain language the nature of the personal data breach and contain at least the information and measures referred to in points (b), (c) and (d) of [Article 33(3)](33.md). 3. The communication to the data subject referred to in paragraph 1 shall not be required if any of the following conditions are met: **(a)** the controller has implemented appropriate technical and organisational protection measures, and those measures were applied to the [personal data](https://www.headlesslaw.com/definitions/gdpr/personal-data) affected by the personal data breach, in particular those that render the personal data unintelligible to any person who is not authorised to access it, such as encryption; **(b)** the controller has taken subsequent measures which ensure that the high risk to the rights and freedoms of data subjects referred to in paragraph 1 is no longer likely to materialise; **(c)** it would involve disproportionate effort. In such a case, there shall instead be a public communication or similar measure whereby the data subjects are informed in an equally effective manner. 4. If the controller has not already communicated the personal data breach to the data subject, the [supervisory authority](https://www.headlesslaw.com/definitions/gdpr/supervisory-authority), having considered the likelihood of the personal data breach resulting in a high risk, may require it to do so or may decide that any of the conditions referred to in paragraph 3 are met. ## Related Level 2 and Level 3 ### Guidance and Q&A - [EDPB 9/2022 — Guideline — Breach notification \[final\]](../level-3/guidelines/edpb-09-2022-breach-notification.md) *** [Chapter IV — Controller and processor](../chapters/iv.md) · [← Article 33](33.md) · [Article 35 →](35.md)