The ClinicalTrials.gov website provides a searchable interface to records of ongoing clinical trials and the results of completed trials. The database can also be searched via the ICTRP and ScanMedicine.
Some ClinicalTrials.gov records are included in the Cochrane Library CENTRAL database.
From May 5 2025 clinical trials from ClinicalTrials.gov will start to be added to Ovid Embase. There will be a new “Clinical Trials” Publication Type limit added that can be used to identify these records in Ovid Embase.
A new version of the interface to ClinicalTrials.gov was made available in 2023. The classic interface was retired in 2024. There was a data migration plan for moving content from the classic interface to the new interface.
The register has more than 533,233 studies (8 April 2025) conducted in 229 countries.
Detailed Help pages are available.
Selected publications:
Califf RM, Cutler TL, Marston HD, Meeker-O’Connell A. The importance of ClinicalTrials.gov in informing trial design, conduct, and results. J Clin Transl Sci. 2025;9:e42.
Default operator AND, terms are also mapped to other search terms
Boolean operators AND, OR, NOT
Phrase searching "breast cancer"
Nesting Yes, for example within the Condition search box it is possible
to search using nested terms:
(colon OR breast) AND (cancer OR neoplasms)
Truncation Not available
Field tags A range of filtering options are available
Hyphens Hyphens are ignored
Help pages Yes
Example (colon OR breast) AND (cancer OR neoplasms)
Saved searches RSS feeds can be set up to provide updates
Export tagged Comma-separated values (CSV), JSON, RIS
Updated 7 October 2025