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Rare Diseases clinical trials recruiting in the U.S.

33 studies for Rare Diseases are recruiting participants at sites across the United States.

A rare disease is one that affects fewer than 200,000 people in the United States. There are nearly 7,000, affecting more than 25 million Americans.

Cities with the most studies

• Boston, MA9 studies
• Chicago, IL8 studies
• Washington, DC8 studies
• Philadelphia, PA7 studies
• Cincinnati, OH5 studies
• Los Angeles, CA5 studies
• Columbus, OH4 studies
• Nashville, TN3 studies
• Pittsburgh, PA3 studies
• Atlanta, GA3 studies
• Houston, TX3 studies
• Seattle, WA3 studies
• Rochester, MN3 studies
• St. Louis, MO3 studies
• New York City, NY3 studies
• Durham, NC3 studies

By state

• California10 studies
• Colorado3 studies
• District of Columbia3 studies
• Florida4 studies
• Georgia3 studies
• Illinois8 studies
• Maryland6 studies
• Massachusetts11 studies
• Minnesota3 studies
• Missouri4 studies
• New York3 studies
• North Carolina6 studies
• Ohio8 studies
• Pennsylvania7 studies
• Tennessee5 studies
• Texas4 studies
• Washington3 studies

Recently updated studies

From ClinicalTrials.gov, data retrieved Sep 30, 2026. Each study sets its own eligibility; the study team decides who can join.