The SNOMED CT Release File Specification formally defines the formats in which SNOMED CT is provided to licensees (Affiliates). For information about SNOMED CT licensing and availability of release files please refer to the Member Licensing and Distribution Service(MLDS) (

Web browsable version: 

SNOMED CT Document Library:

© Copyright 2024 International Health Terminology Standards Development Organisation, all rights reserved.

This document is a publication of International Health Terminology Standards Development Organisation, trading as SNOMED International.  SNOMED International owns and maintains SNOMED CT®.

Any modification of this document (including without limitation the removal or modification of this notice) is prohibited without the express written permission of SNOMED International. This document may be subject to updates. Always use the latest version of this document published by SNOMED International. This can be viewed online and downloaded by following the links on the front page or cover of this document.

SNOMED®, SNOMED CT® and IHTSDO® are registered trademarks of International Health Terminology Standards Development Organisation. SNOMED CT® licensing information is available at For more information about SNOMED International and SNOMED International Membership, please refer to or contact us at

Latest PDF Version for Download:


This PDF document was generated from the web version on . Any changes made to the web pages since this date will not appear in the PDF. For information about recent changes please see Recent Updates.


1. Introduction

2 SNOMED CT Logical Model

3 Release Types, Packages and Files

4 Component Release Files Specification

5 Reference Set Release Files Specification

6 SNOMED CT Identifiers

Appendix A: Notes on Release File Changes

Appendix B. Specification Reference Information

Appendix C. Unicode UTF-8 encoding

Appendix D: Concept Definition Illustrations

Appendix E: Concept Enumerations

Previous Versions

Recent Updates