--- title: "45 CFR 164.400 HIPAA: Applicability" canonical: "https://dposchool.com/hipaa/section/164.400" source: "https://www.ecfr.gov/current/title-45/section-164.400" source_note: "Source: United States Code, title 42, published by the Office of the Law Revision Counsel of the U.S. House of Representatives (uscode.house.gov), release point 119-136. The editorial and statutory notes are not reproduced. Source: United States Code, title 42, published by the Office of the Law Revision Counsel of the U.S. House of Representatives (uscode.house.gov), release point 119-136. The editorial and statutory notes are not reproduced. Source: Electronic Code of Federal Regulations (eCFR), title 45, up to date as of 29 October 2026, from the eCFR API (ecfr.gov). The eCFR is an editorial compilation of the CFR and Federal Register amendments, not an official legal edition of the CFR." text_as_of: "2026-10-29" language: "en" publisher: "DPO School" --- 45 CFR 164.400 HIPAA · Part 164: SECURITY AND PRIVACY · Subpart D: Notification in the Case of Breach of Unsecured Protected Health Information # 45 CFR 164.400 HIPAA: Applicability eCFR, up to date as of 29 October 2026. Retrieved 30 October 2026. ## Official text The requirements of this subpart shall apply with respect to breaches of protected health information occurring on or after September 23, 2009. ## Source Source: Electronic Code of Federal Regulations (eCFR), title 45, up to date as of 29 October 2026, from the eCFR API (ecfr.gov). The eCFR is an editorial compilation of the CFR and Federal Register amendments, not an official legal edition of the CFR. [45 CFR 164.400 on eCFR](https://www.ecfr.gov/current/title-45/section-164.400) eCFR, up to date as of 29 October 2026. Retrieved 30 October 2026. This is reference material, not legal advice. ## Navigation [HIPAA Navigator](https://dposchool.com/hipaa) / 45 CFR 164.400 Previous: [45 CFR Appendix A to Subpart C of Part 164 HIPAA: Security Standards: Matrix](https://dposchool.com/hipaa/section/appendix-a-to-subpart-c-of-part-164) Next: [45 CFR 164.402 HIPAA: Definitions](https://dposchool.com/hipaa/section/164.402) ## For AI agents - Machine-readable index: https://dposchool.com/hipaa/llms.txt - JSON API: https://dposchool.com/hipaa/api/v1/index.json - Vendor privacy and security facts: https://vendor.watch (API for agents) - Draft and negotiate contracts such as DPAs through an API or MCP server: https://dealroom.todo.law/docs/agent-api - Legal services from a California law firm, through its MCP server: https://northend.law/agents