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How to License and Access the Unified Medical Language System® (UMLS®) Data


UMLS licenses are issued only to individuals and not to groups or organizations. You must accept the terms of the UMLS Metathesaurus License (PDF) and create a UMLS Terminology Services (UTS) account for access to the UMLS, terminology browsers, and related resources such as RxNorm and SNOMED CT®.

Each UMLS Release contains the three Knowledge Sources: the Metathesaurus, the Semantic Network, and the SPECIALIST Lexicon. A complete description of the Knowledge Sources and their distribution formats can be found on the UMLS Web site.

There is no charge for licensing any part of the UMLS from NLM. There may be separate license fees associated with usage of SNOMED CT which is owned by the International Health Terminology Standards Development Organization (IHTSDO). The SNOMED CT® Affiliate Licence Agreement is included as Appendix 2 of the UMLS Metathesaurus License and outlines possible costs. NLM is a member of IHTSDO and there is no charge for SNOMED CT use in the United States and other member countries.  For information about fees in non-member countries, see the IHTSDO web site.

Users should carefully read the license agreement before re-distributing any content in any type of application as there may be additional restrictions, permissions or copyright considerations imposed by the content providers. Users must contact the vocabulary content providers regarding any use that is not covered by the license. The content providers may charge fees for these additional uses of their content. Appendix 1 lists contact information for each content provider.

For more information please see the UMLS FAQ page.

How to Request a License and Create a UTS Account

  1. Please sign up for a new UMLS Terminology Services (UTS) account with your preferred identity provider at the UTS homepage.
  2. Complete and submit the license request form. NLM will send the license approval e-mail within 5 business days after reviewing your authenticated license request.
  3. You will sign in using identity provider credentials to download files or access web interfaces that require UTS authentication such as the UTS, VSAC, SNOMED CT, or RxNorm.

If you need assistance, please visit UMLS FAQ or write to the NLM Customer Support. Use the subject line: "UMLS License Request."

How to Access UMLS Data

Sign in to the UTS to access applications, downloads, and application programming interfaces (APIs) .

Browse UTS Applications

You can search the data through UTS applications such as:

  • Metathesaurus Browser - Retrieve UMLS concept information, including CUIs, semantic types, and synonymous terms.
  • Semantic Network Browser - View the names, definitions, and hierarchical structure of the Semantic Network.


The UTS provides access to files from the UMLS Knowledge Sources, RxNorm, SNOMED CT, and Value Sets.

API Options

Use our application programming interfaces (APIs) to query the UMLS data within your own application. More information is available on the UMLS API home page.

Reporting Requirements

UMLS Metathesaurus Annual Report

As part of the license agreement, you agree to provide NLM with a yearly report of how you used the UMLS. The report is due every January. NLM will send several e-mail reminders in January and you will complete the report through your UTS profile. If the Annual Report is not completed by the deadline, you forfeit access to the UTS and your license will be terminated.

IHTSDO Affiliate License Statement of Account

The SNOMED CT® Affiliate Licence Agreement is included as Appendix 2 of the UMLS Metathesaurus License. Within this license, you agree to report to the SNOMED International on your usage of SNOMED CT in non-Member countries. This report is imbedded within the UMLS Annual Report. Complete details are available from SNOMED International.

Data Use Restrictions

Section 12 of the UMLS Metathesaurus License outlines additional restrictions on source vocabulary use. These restrictions apply to the vocabularies listed in Appendix 1 of the license agreement.

SNOMED CT usage restrictions are outlined in Appendix 2 of the license agreement Licensees of the UMLS Metathesaurus have free access to SNOMED CT. The IHTSDO license terms for SNOMED CT cover use and distribution worldwide, but fees may be applicable outside IHTSDO Member countries.

For more information, visit NLM's SNOMED CT FAQ. Please contact NLM Customer Support for UMLS licensing questions or use of SNOMED CT in the US. For questions regarding use of SNOMED CT in non-member territories or for fees please contact the IHTSDO.

Contact Information

Questions about obtaining a UMLS Metathesaurus License? Please write to NLM Customer Support. Use the subject line: "UMLS License Request."

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Last Reviewed: March 2, 2022