is a web-based resource that provides patients, their family members, health care professionals, researchers, and the public with easy access to information on publicly and privately supported clinical studies on a wide range of diseases and conditions. is maintained by the National Library of Medicine (NLM) at the National Institutes of Health (NIH). Information on is provided and updated by the sponsor or principal investigator of the clinical study. Studies are generally submitted/registerd to when they begin, and the information on the site is updated throughout the study. In some cases, results of the study are submitted after the study ends. is commonly referred to as a "registry and results database“ of clinical studies.

Protocol Registration and Results system (PRS)

PRS User's Guide

PRS Guided Tutorials

Submit Studies

UA Guidelines for

UA Registration and Results Requirements Decision Tree Registration & Results Reporting Checklist