Ontology Lookup Service logo

Ontology Lookup Service

May 4th, 2016 - This version of OLS is deprecated, please use the new site at http://www.ebi.ac.uk/ols. We will continue to provide access to this service at http://www.ebi.ac.uk/ols/v2 until October 2016, however, the underlying database is no longer being updated. This service will be removed entirely from October 2016. We apologies in advance for any inconvenience caused, if you have any questions please contact us on ols-support [at] ebi.ac.uk.
Enter Ontology Term

(Include obsolete terms )

Enter a partial search term. As you are typing, you will see suggested terms that match what are you have typed so far. If you select a term from the pull-down list, its corresponding ID will be displayed in the form. If you see "... and more" in the list of suggested values, you can select this value to be redirected to a page where all possible values are listed. As an example, enter mitoc in the Term Name box while the Gene Ontology is selected.

For better search results, do not type punctuation or symbols. For example, if you are looking for 4'-(L-tryptophan), try typing 4 L tryp.

You can browse an ontology by clicking on the "browse" button next to the ontology selector. To view the complete ontology, do not select a term name. If a term name has been selected, it will be the root from which the ontology will be browsed.

Simple Term ID Search:

Enter a complete term ID (example: GO:0008150) and click on the 'Search' button to quickly obtain all pertinent information for this term. Searches are case-sensitive, so ensure that the proper ontology prefix is used (GO:, rather than go: or Go:).


The Ontology Lookup Service is a spin-off of the PRIDE project, which required a centralized query interface for ontology and controlled vocabulary lookup.

The OLS provides a web service interface to query multiple ontologies from a single location with a unified output format.The OLS can integrate any ontology available in the Open Biomedical Ontology (OBO) format.

OLS Statistics

Version 1.21
Ontologies 93
Terms 2685446
Last updated Fri Sep 09 17:24:23 BST 2016
See the full breakdown of loaded ontologies here and load statistics here.

Citing OLS

Côté R, Reisinger F, Martens L, Barsnes H, Vizcaino JA, Hermjakob H. The Ontology Lookup Service: bigger and better. Nucleic Acids Res. 2010 May 11. PMID: 20460452

Developer Documentation

The OLS is an open source project hosted on Google Code. You can access the OLS project page, or browse the SVN repository.

External collaborators have provided an R package to connect to and query the OLS. It is available through github and described on the bioconductor website.



Please supply your feedback to the OLS helpdesk. We thank you for your help in further developing the OLS.

You may also wish to submit a publicly visible feature request or bug report


The OLS software and the SOAP webservice are both freely available for use for all users, academic or commercial, under the terms of the Apache License, Version 2.0. If you find them useful for your own applications, we would be grateful for a mention similar to the following:

"Uses the EBI OLS <http://www.ebi.ac.uk/ols>."

where both the image and URL are hyperlinked to the OLS homepage.

OLS SOAP Demo client (java): ols-client.tar.gz

A weekly MySQL database export file can be downloaded from the EBI public FTP directory. Instructions on how obtain, install and use the export file can be found on the MySQL database export documentation page.


  • OLS is supported through BBSRC iSPIDER.
  • Hosted by Google Code