Metathesaurus Downloads

This page contains hyperlinks to most of the files associated with the NCI Metathesaurus (NCIm) distribution, the exception being the actual NCIm data files which requires validation of your UMLS credentials. The NCIm is built on top of a subset of the National Library of Medicine's (NLM) UMLS Metathesaurus, use of which is restricted under the UMLS license agreement and requires us to validate your UMLS license. This validation is done from a separate page (see "NCI Metathesaurus Data File Downloads" below).

If you don't have a UMLS account, please request one from the NLM. Follow the "Metathesaurus License" link in the NLM's UMLS Metathesaurus page to request a license.

NCI Metathesaurus Data File Downloads

This distribution contains the NCI Metathesaurus version 202402 and is based on the UMLS build 2023AB. The NCI Metathesaurus (NCIm) is built on top of a subset of the National Library of Medicine's (NLM) UMLS Metathesaurus, use of which is restricted under the UMLS license agreement and requires us to validate your UMLS license.

If you do not have an active UMLS Terminology Services Account, please Sign up.

To download the distribution:

  1. Identify your NLM API KEY by signing in to your UMLS Account and clicking on the “My Profile” button.
  2. Enter your API KEY to validate your UMLS account and enable the download link below. If your account does not validate correctly, please request a new one from the NLM.
  3. Download NCI Metathesaurus

If your account does not validate correctly, please request a new one from the NLM.

Important. Please be advised that if you validate your api key and then navigate away from this page without having downloaded the NCI Metathesaurus RRF files, you might need to revalidate your UMLS credentials again before you can download the files.

The NCI Metathesaurus in RRF format contains the distribution (over 20 files) of the NCI Metathesaurus in the NLM's Rich Release Format (RRF). Documentation for the RRF is in the UMLS Reference Manual. While the table structures are the same, there are content differences such as which terminology sources are included and how concepts are edited.

NCI_RRF_Addendum.pdf:
The addendum to NLM's RRF documentation describes NCI-specific changes to the UMLS Metathesaurus RRF structure as follows: any term types, source precedence order, sources, and the relationship attributes in the NCI Metathesaurus that may be different from the UMLS Metathesaurus.