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Unified Medical Language System® (UMLS®)

UMLS Knowledge Sources: File Downloads

Release Information
MetamorphoSys Installation Help

2021AA Full UMLS Release Files

Release Description File Size (compressed) File Size (uncompressed) Date
Full Release ( The full release includes the UMLS Metathesaurus, Semantic Network, Specialist Lexicon and Lexical Tools, database load scripts, and MetamorphoSys for customizing your UMLS subset and browsing the data. 5.0 GB 33.4 GB May 3, 2021

Download Notes:

  • Download the UMLS zip file and extract the contents to a single directory.
  • Read the README file after downloading, which includes information on installing the UMLS Knowledge Sources and highlights changes for this release.
  • Each UMLS release includes MetamorphoSys, required to install Knowledge Sources files, and to create, search and browse customized Metathesaurus subsets. MetamorphoSys requires a minimum of 40 GB of free hard disk and takes 2-10 hours to run on a range of platforms tested. The actual time will depend on your configuration, hardware and operating system platforms.

2021AA UMLS Metathesaurus Files

Release Description File Size (compressed) File Size (uncompressed) Date
UMLS Metathesaurus Files Download the UMLS Metathesaurus files if you want to load the complete Metathesaurus data directly into your local environment without any subsetting or additional customization. MYSQL and Oracle load scripts are included. This release does not include MetamorphoSys, the Semantic Network, or the Specialist Lexicon and Lexical Tools. To browse the UMLS Metathesaurus data, visit the UMLS Metathesaurus Browser. 4.7 GB 31.7 GB May 3, 2021
MRCONSO.RRF The most widely used UMLS file. This file includes names, codes, and concepts from over 200 source vocabularies. More information... 425 MB 2.0 GB May 3, 2021

UMLS Release Archives 2004-2020AB
UMLS Release Archives 2002-2003

Last Reviewed: May 3, 2021