Company lists · Data refreshed September 2026
Top 25 Medical volunteer organizations based in the United States
RevenueBase identified 334 medical volunteer organizations headquartered in the United States as of September 2026 and tracks 61,847 professional contacts across them, including 8,282 with verified work emails. New York is the largest hub.
This list covers medical volunteer organizations 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, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 17, 2026.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, 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.
The 25 largest medical volunteer organizations based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 26,563 contacts → | ||||
Partial evidence “The American Red Cross prevents and alleviates human suffering in the face of emergencies by mobilizing the power of volunteers and the generosity of donors.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 2 | 24,886 contacts → | ||||
Indirect evidence “International Mission of Mercy (IMM) was founded in 1991 by Satish Mehtani, a veteran of disaster relief missions in Kuwait, Japan and at the World Trade Center following…” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 3 | 4,409 contacts → | ||||
Partial evidence “International Medical Corps is a global first responder that delivers emergency medical and related services to those affected by conflict, disaster and disease, no matter where…” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 4 | 990 contacts → | ||||
Indirect evidence “People in crisis are dying from preventable causes.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 5 | 556 contacts → | ||||
Partial evidence “The Buddhist Tzu Chi Foundation (Tzu Chi USA) is a volunteer-based international non-governmental organization established by Dharma Master Cheng Yen in Hualien, Taiwan, in 1966.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 6 | 549 contacts → | ||||
Indirect evidence “For 45 years, we have been a beacon of health and hope for communities worldwide, confronting pressing health challenges.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 7 | 216 contacts → | ||||
Partial evidence “Remote Area Medical (RAM) is a national nonprofit provider of free pop-up clinics.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 8 | 211 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 9 | 168 contacts → | ||||
Indirect evidence “Heart to Heart International seeks to improve healthcare access in the U.S.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 10 | 101 contacts → | ||||
Indirect evidence “Our mission is to provide affordable, accessible, quality health care, promote learning opportunities for students of health professions, end homelessness, and improve the quality…” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 11 | 99 contacts → | ||||
Indirect evidence “Global Links is a Pittsburgh-based non-profit dedicated to improving health in communities with need.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 12 | 64 contacts → | ||||
Partial evidence “FIMRC was founded in 2002 with the mission of improving access to medical care for underprivileged children around the world.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 13 | 45 contacts → | ||||
Indirect evidence “Based in Charlotte, NC, Care Ring leads a collaborative effort to meet our community's changing health care needs and to fight racial and economic disparities in health outcomes.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 14 | 42 contacts → | ||||
Indirect evidence “CIHVA is the 2nd busiest ambulance service in Suffolk County, NY.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 15 | 42 contacts → | ||||
Partial evidence “Since 1995, Mercy & Truth Medical Missions has been dedicated to delivering quality healthcare while sharing the Gospel with underserved communities in Central America, South…” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 16 | 41 contacts → | ||||
Partial evidence “Our Mission: Expanding access to healthcare; empowering students and volunteers to tackle global health challenges Timmy Global Health expands access to healthcare and empowers…” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 17 | 34 contacts → | ||||
Partial evidence “Founded at Temple University, Health-Link Society (HLS) is a non-profit organization that is dedicated to providing volunteering opportunities within marginalized and local…” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 18 | 34 contacts → | ||||
Indirect evidence “Good Samaritan Clinic provides free, high-quality, respectful healthcare to uninsured adults and families in the Midlands of South Carolina.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 19 | 31 contacts → | ||||
Indirect evidence “Good News Clinics is a historic organization that began serving patients 25 years ago in 1992.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 20 | 30 contacts → | ||||
Indirect evidence “The Haitian Health Foundation's mission is to improve the health and well-being of women, children, families, and communities through healthcare, education, and community…” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 21 | 29 contacts → | ||||
Partial evidence “We are an agile crisis response team providing tailored emergency medical care, situation analysis, and clinical capacity-building for populations displaced by conflict or…” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 22 | 27 contacts → | ||||
Partial evidence “We are committed to delivering the highest level of medical care available today to remote areas worldwide.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 23 | 24 contacts → | ||||
Partial evidence “We are a humanitarian medical resource organization that is committed to uniting non-profits to save lives and relieve suffering of those who need basic health care.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 24 | 23 contacts → | ||||
Indirect evidence “Brother’s Brother Foundation helps bridge the gap between aid and sustainability by supporting localized programs and providing essential resources in the areas of healthcare…” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
| 25 | 22 contacts → | ||||
Indirect evidence “SPARTA AMBULANCE SERVICE INC is a company based out of SPARTA, New Jersey, United States.” Source: RevenueBase Database · checked Sep 17, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: medical volunteer organizations. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names medical volunteer organizations.
- Partial evidence
- Its own public description names part of medical volunteer organizations, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name medical volunteer organizations. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 334 medical volunteer organizations based in the United States
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Medical volunteer organizations based in the United States at a glance
As of Sep 17, 2026Companies by employee count
Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 334 companies.
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 medical volunteer organizations, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search 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 Smart Search, 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 “medical volunteer organizations”. Matching reads each company's description, not its industry code or its name.
- RevenueBase Smart Search
- RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names medical volunteer organizations), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
- What we exclude
- Companies whose own description does not clearly place them among medical volunteer organizations, 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 its RevenueBase Smart Search 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, 8,282 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 17, 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
What is RevenueBase Smart Search?
RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names medical volunteer organizations, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.
How many medical volunteer organizations are there based in the United States?
RevenueBase identified 334 medical volunteer organizations 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?
American RED Cross, headquartered in Washington, tops this list with the largest team on record.
Which city has the most medical volunteer organizations?
New York leads with 12 headquartered companies, followed by Los Angeles (10) and Atlanta (6).
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 8,282 verified decision-maker contacts tracked across these 334 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 17, 2026.
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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 Smart Search, 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.
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