Company lists · Data refreshed September 2026

Top 25 Patient recruitment services based in the United States

RevenueBase identified 1,179 patient recruitment services headquartered in the United States as of September 2026 and tracks 63,466 professional contacts across them, including 28,099 with verified work emails and 18,639 with mobile numbers. Miami is the largest hub.

This list covers patient recruitment services headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, how directly it supports the match, and when it was last checked. Data refreshed September 5, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase SmartSearch, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row Match evidence on every row Refreshed Sep 5, 2026 86% judged on-target in blind review
1,179Companies
63,466Contacts tracked
28,099Verified emails
18,639Mobile numbers
Unlock all 1,179 companies Free signup · no credit card · 500 free credits

The 25 largest patient recruitment services based in the United States

Ranked by team size
Top 25 of 1,179 patient recruitment services based in the United States, ranked by team size, largest first. Data refreshed Sep 5, 2026. Evidence rates how directly each company's own description names patient recruitment services: strong (names it), partial (names part of it), indirect (matched on its full profile rather than the summary shown). Click a count to unlock that company's people.
#CompanyHeadquartersEmployeesContacts
1
PPDIndirect evidence
Waltham, MA, United StatesHQ checked Sep 5, 202610001+20,530

“The PPD™ clinical research business of Thermo Fisher Scientific, the world leader in serving science, enables customers to accelerate innovation and drug development through…”

Source: company website · checked Sep 5, 2026
2
PRA Health SciencesIndirect evidence
Raleigh, NC, United StatesHQ checked Sep 5, 202610001+4,708

“PRA is now an ICON plc company.”

Source: company website · checked Sep 5, 2026
3
Worldwide Clinical TrialsIndirect evidence
Research Triangle Park, NC, United StatesHQ checked Sep 5, 20261,001-5,0003,440

“Worldwide Clinical Trials (Worldwide) is a global CRO serving development-driven biopharmaceutical companies, with more than 4,400 professionals operating across more than 70…”

Source: company website · checked Sep 5, 2026
4
Precision For MedicineIndirect evidence
Bethesda, MD, United StatesHQ checked Sep 5, 20261,001-5,0001,781

“Precision for Medicine is an industry-leading global clinical research services organization, purpose-built to improve the clinical research and development process for new…”

Source: company website · checked Sep 5, 2026
5
SuvodaIndirect evidence
Conshohocken, PA, United StatesHQ checked Sep 5, 20261,001-5,0001,255

“Suvoda is a global clinical trial technology company, now strengthened by our merger with Greenphire.”

Source: company website · checked Sep 5, 2026
6
CelerionIndirect evidence
Lincoln, NE, United StatesHQ checked Sep 5, 20261,001-5,0001,080

“Celerion, a leader in early clinical research, delivers Applied Translational Medicine.”

Source: company website · checked Sep 5, 2026
7Covington, KY, United StatesHQ checked Sep 5, 20261,001-5,0001,043

“CTI Clinical Trial and Consulting Services is a global, privately held, research service organization, delivering a complete spectrum of clinical trial and consulting services…”

Source: company website · checked Sep 5, 2026
8
Navitas Life SciencesIndirect evidence
Gaithersburg, MD, United StatesHQ checked Sep 5, 20261,001-5,000990

“Navitas Life Sciences is a global Clinical Research partner with over 35 years of expertise in Clinical, Regulatory, Safety, and Data Management solutions.”

Source: company website · checked Sep 5, 2026
9Durham, NC, United StatesHQ checked Sep 5, 20261,001-5,000971

“Velocity is the world’s leading organization of fully integrated clinical research sites.”

Source: company website · checked Sep 5, 2026
10
EMMESIndirect evidence
Rockville, MD, United StatesHQ checked Sep 5, 20261,001-5,000961

“Emmes is a Contract Research Organization delivering complex clinical trials through therapeutic expertise, scientific rigor, and technology-enabled execution.”

Source: company website · checked Sep 5, 2026
11
CenexelIndirect evidence
Salt Lake City, UT, United StatesHQ checked Sep 5, 20261,001-5,000847

“CenExel is a leading integrated, wholly owned, nationwide clinical research site network comprised of 18 Centers of Excellence in major metropolitan areas across the U.”

Source: company website · checked Sep 5, 2026
12
MMGStrong evidence
Rockville, MD, United StatesHQ checked Sep 5, 2026n/a770

“MMG is a full-service global health communications group that specializes in patient recruitment and retention.”

Source: company website · checked Sep 5, 2026
13
CaidyaIndirect evidence
Raleigh, NC, United StatesHQ checked Sep 5, 20261,001-5,000758

“Caidya is a multi-therapeutic clinical research organization (CRO) serving innovators worldwide.”

Source: company website · checked Sep 5, 2026
14
RHOIndirect evidence
Durham, NC, United StatesHQ checked Sep 5, 2026501-1,000732

“Experience the Cohesion Effect.”

Source: company website · checked Sep 5, 2026
15
DM Clinical ResearchIndirect evidence
Houston, TX, United StatesHQ checked Sep 5, 2026501-1,000590

“DM Clinical Research is a network of clinical trial investigator sites with headquarters based out of Houston, Texas.”

Source: company website · checked Sep 5, 2026
16Horsham, PA, United StatesHQ checked Sep 5, 20261,001-5,000561

“Accelerated Enrollment Solutions (AES) is now Trialmed.”

Source: company website · checked Sep 5, 2026
17
ChilternIndirect evidence
Durham, NC, United StatesHQ checked Sep 5, 202610001+532

“THIS PAGE IS NOT MONITORED.”

Source: company website · checked Sep 5, 2026
18
Catalyst Clinical ResearchIndirect evidence
Wilmington, NC, United StatesHQ checked Sep 5, 20261,001-5,000513

“Catalyst Clinical Research is now Worldwide Clinical Trials.”

Source: company website · checked Sep 5, 2026
19
SiteroIndirect evidence
Coral Gables, FL, United StatesHQ checked Sep 5, 2026501-1,000389

“Sitero is a next-generation, site-focused clinical research organization (CRO) for life sciences and institutional research organizations that helps get treatments to market safer…”

Source: company website · checked Sep 5, 2026
20
Tech ObserverIndirect evidence
Paramus, NJ, United StatesHQ checked Sep 5, 2026501-1,000329

“Global Reach; Local Expertise Headquartered in Paramus, New Jersey, USA with offices in Singapore, Denmark, UK, and India, our exceptional team of 500+ professionals serves…”

Source: company website · checked Sep 5, 2026
21
Flourish ResearchIndirect evidence
Apex, NC, United StatesHQ checked Sep 5, 2026501-1,000321

“Flourish Research is a fully integrated, multi-site clinical trial network serving sponsors and CROs across North America.”

Source: company website · checked Sep 5, 2026
22
Florence HealthcareIndirect evidence
Atlanta, GA, United StatesHQ checked Sep 5, 2026201-500295

“Florence is a purpose-built platform that connects sponsors and sites to accelerate clinical trials, improve operational capacity, and reduce risk.”

Source: company website · checked Sep 5, 2026
23
Science 37Partial evidence
Morrisville, NC, United StatesHQ checked Sep 5, 2026201-500291

“Science 37 is a modern clinical research site that delivers trials directly to patients’ homes.”

Source: company website · checked Sep 5, 2026
24
PCM TrialsIndirect evidence
Denver, CO, United StatesHQ checked Sep 5, 20261,001-5,000260

“PCM Trials acquired EmVenio Research and Netherlands-based Clinical Trials Service in 2024.”

Source: company website · checked Sep 5, 2026
25
Elligo Health ResearchPartial evidence
Austin, TX, United StatesHQ checked Sep 5, 2026201-500254

“Elligo Health Research is an integrated research organization founded to bridge the gap between cutting-edge clinical trials and the patients who need them-an idea that sparked…”

Source: company website · checked Sep 5, 2026

Showing 25 of 1,179 patient recruitment services based in the United States

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Patient recruitment services based in the United States at a glance

As of Sep 5, 2026
11-50Median size (employees)
MiamiLargest hub · 57 HQs
18,639Contacts with mobile numbers
Sep 5, 2026Data refreshed

Companies by employee count

1-10
476
11-50
453
51-200
171
201-500
37
501-1,000
13
1,001-5,000
22
5,001-10,000
1
10001+
4

Verified emails by last verification

0–30
25,850
31–60
1,984
61–90
32
90–180
17
180+
216

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among patient recruitment services, so some rows will be adjacent to the category rather than pure plays. The description and evidence rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase SmartSearch, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in the United States whose own description of what they do matches “patient recruitment services”. Matching reads each company's description, not its industry code or its name.
What we exclude
Companies whose own description does not clearly place them among patient recruitment services, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and an evidence rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking
Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification
Every listed company carries at least one verified work email, 28,099 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh
This page's figures were pulled from the company graph on September 5, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Frequently asked

How many patient recruitment services are there based in the United States?

RevenueBase identified 1,179 patient recruitment services headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

PPD, headquartered in Waltham, tops this list with the largest team on record.

Which city has the most patient recruitment services?

Miami leads with 57 headquartered companies, followed by Houston (34) and New York (28).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 28,099 verified decision-maker contacts tracked across these 1,179 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 5, 2026.

Ready to reach these companies? Verified emails and direct dials for all 1,179 patient recruitment services based in the United States. Start with a free account, no credit card.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase SmartSearch, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.