Skip Navigation Bar

Unified Medical Language System® (UMLS®)

UMLS - Frequently Asked Questions

Click on a topics to reveal its questions and answers or click "expand all" to reveal all of the questions and answers.

Expand All  Collapse All


How do I sign up for a UMLS license?

Are there any fees for the UMLS License?

  • There are no fees for the UMLS Metathesaurus License.
  • Appendix 2 of the license, the SNOMED CT Affiliate Licence Agreement, refers to fees for the use of SNOMED CT. Note that:

Is an organizational license available?

Licenses are registered to individuals. There are no organizational or enterprise licenses.

Does everyone in my organization need a license?

NLM requires at least once licensee per organization. However it is fine to have multiple licensees from the same organization. Each person who requires access to the browsers and/or downloads must have their own license. We do not encourage users to share account information with one another.

Are there special rules for vendors or other commercial organizations?

There is not a separate license for commercial organizations. However if your product incorporates data from the UMLS, you must have a license. Additionally we require that your clients have a license as well. The same license and rules apply to all users.

Where can I get a copy of the license?

I have questions about a specific vocabulary that are not covered by the license agreement.

Contact the content provider directly to ensure that your use is covered by the UMLS License. Appendix 1 of the license lists contact information for each vocabulary.

Reporting Requirements

What is the UMLS 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.

What is the SNOMED CT Affiliate Report?

As mentioned in the SNOMED CT Affiliate License Agreement, you agree to report to the IHTSDO on your usage of SNOMED CT in non-Member countries. This report should be submitted to the IHTSDO through their Member Licensing and Distribution Service before starting activities in non-Member countries. Complete details are available from the IHTSDO at A list of member countries is available at


How do I download files?

There are two ways to access the downloads:

What terminology and mapping files are available for download?

Go to the Downloads Homepage to view available downloads.

UMLS Releases and Documentation

How often is the UMLS released?

The UMLS is updated in May and November of each year. The May release is the AA release (ex. 2015AA) and the November release is the AB Release (ex. 2015AB).

Where are the release notes?

The Release homepage includes release notes, bugs, metadata, and statistics for the latest version of the UMLS.
To view older release notes, go to the Release Documentation Archive.

Where can I get more information about the UMLS?

Get Started
Begin learning about the UMLS with these tools:

Technical Documentation
The UMLS Reference Manual provides an overview of the UMLS and:

The Source Release Documentation has a summary, metadata and statistics for each vocabulary in the UMLS Metathesaurus. It includes Metathesaurus representation and source representation pages for selected vocabularies. The representation pages detail how the original source information is reflected in the Metathesaurus.

Additional technical documentation: Sample database queries and load scripts

MetamorphoSys (Local Installation of the UMLS)
View the MetamorphoSys homepage for help with your local installation of the UMLS.

UMLS users are encouraged to subscribe to this list, to share their experiences with, or seek advice from the UMLS community on using UMLS resources. NLM also uses this forum to distribute official announcements about UMLS products and services.

UTS, Browsing, User Account

What is the UTS?

The UMLS Terminology Services (UTS) Web site gives you access to the UMLS browsers, downloads, and APIs.

What is my username and password?

You create a username and password as part of the license application. If you cannot remember your username or password, the UTS Sign In page provides options to retrieve your username and reset your password.

Related FAQ

Other frequently asked questions for the UMLS resources:

Contact Us

We welcome any questions and comments via our contact form.