Largest primary care groups in Massachusetts
- Groups
- 677
- Internal Medicine groups
- 339
- Nurse Practitioner groups
- 200
- Internal medicine specialists
- 8,000
- Nurse practitioner specialists
- 498
There are 677 primary care groups in Massachusetts with a Medicare PAC ID: 339 internal medicine, 200 nurse practitioner, 105 family medicine, 27 physician assistant, 3 clinical nurse specialist and 3 general practice. Massachusetts General Physicians Organization (MGPO) is the largest internal medicine group, with 1,331 internal medicine specialists, and Walk-In MD Urgent Care the largest nurse practitioner group, with 15 nurse practitioner specialists.
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Massachusetts General Physicians Organization (MGPO) is the largest primary care group in Massachusetts, with 3,803 physicians
Ranked by physicians with a Massachusetts address linked to each group. Massachusetts General Hospital is second with 3,723, and Brigham and Women's Hospital third with 3,175. 56 Massachusetts groups have 100 or more physicians.
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Showing 1 to 10 of 677 primary care groups in Massachusetts
Sources: Doctors and Clinicians National Downloadable File (CMS) and Dmand AI Affiliation Data
Massachusetts General Physicians Organization (MGPO) is the largest internal medicine group in Massachusetts, with 1,331 internal medicine specialists
Ranked by internal medicine specialists with a Massachusetts address linked to each group whose main sub-specialty is internal medicine. Massachusetts General Hospital is second with 1,290, and Brigham and Women's Hospital third with 1,204.
Sources: Doctors and Clinicians National Downloadable File (CMS) and Dmand AI Affiliation Data
Walk-In MD Urgent Care is the largest nurse practitioner group in Massachusetts, with 15 nurse practitioner specialists
Ranked by nurse practitioner specialists with a Massachusetts address linked to each group whose main sub-specialty is nurse practitioner. New Horizon Medical is second with 11, and Crausman Medical Associates third with 11.
Sources: Doctors and Clinicians National Downloadable File (CMS) and Dmand AI Affiliation Data
Boston University Department of Family Medicine is the largest family medicine group in Massachusetts, with 85 family physicians
Ranked by family physicians with a Massachusetts address linked to each group whose main sub-specialty is family medicine. Greater Lawrence Family Health Center is second with 83, and South Boston Community Health Center third with 42.
Sources: Doctors and Clinicians National Downloadable File (CMS) and Dmand AI Affiliation Data
UH Partners (UHP) is the largest physician assistant group in Massachusetts, with 26 physician assistant specialists
Ranked by physician assistant specialists with a Massachusetts address linked to each group whose main sub-specialty is physician assistant. Brown Health Neurosurgery Medical Group is second with 9, and Acton Urgent Care third with 9.
Sources: Doctors and Clinicians National Downloadable File (CMS) and Dmand AI Affiliation Data
North Shore Nurse Practitioner Associates and Hanover Psychiatry Group have the most clinical nurse specialist specialists of any Massachusetts clinical nurse specialist group, with 2 each
Ranked by clinical nurse specialist specialists with a Massachusetts address linked to each group whose main sub-specialty is clinical nurse specialist.
Sources: Doctors and Clinicians National Downloadable File (CMS) and Dmand AI Affiliation Data
Tufts Medicine Care at Home and Joshi Medical have the most general practice specialists of any Massachusetts general practice group, with 1 each
Ranked by general practice specialists with a Massachusetts address linked to each group whose main sub-specialty is general practice.
Sources: Doctors and Clinicians National Downloadable File (CMS) and Dmand AI Affiliation Data
Mass General Brigham has the most physicians in Massachusetts primary care groups, with 7,169 across 14 groups
Dmand AI maps every medical group to its parent organization, up to the health system or platform at the top. 38 parent organizations have two or more Massachusetts primary care groups. Among health systems, Beth Israel Lahey Health has the most groups, 16. Each clinician counts once per parent organization.
See every medical group, site and clinician under Mass General Brigham
Org Hierarchy Explorer maps every group, site of care and clinician under the parent, with the leaders at each group.
Source: Dmand AI Org Hierarchy Data
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Dmand AI maps the owners, administrators and physician leaders at each of the 677 Massachusetts primary care groups, with the parent organization above each one, and finds validated work emails and mobile numbers.
61% of Massachusetts primary care groups are independent, with no larger parent organization
A group counts as independent when no health system, platform or other organization sits above it in the org hierarchy. Every other group belongs to a larger organization.
Massachusetts primary care groups by ownership
- Independent411
- Health system or hospital114
- Platform or corporate owner81
- Community or government31
- Other organization40
Sites of care beyond their own offices
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Dmand AI maps each group to the health system, physician platform or management company above it, so you can sell to the owner, not one site.
Source: Dmand AI Org Hierarchy Data
175 Massachusetts primary care groups practice at a hospital site, and 61 at an FQHC
Sites of care linked to each group in the org hierarchy, beyond its own offices. A group can practice at several kinds of site.
Massachusetts primary care groups by site of care
- Hospitals175
- FQHCs61
- Skilled nursing facilities37
- Behavioral health facilities15
- Ambulatory surgery centers11
- Hospices11
- Dialysis centers7
- Rural health clinics4
- Therapy and rehab centers3
- Home health agencies3
Clinicians in Massachusetts primary care groups
Sources: Dmand AI Practice Data and Dmand AI Org Hierarchy Data
Boston has the most primary care groups in Massachusetts, with 46
More Massachusetts cities with primary care groups
- Brockton13
- Framingham12
- Chelmsford11
- Fall River11
- Lawrence11
- Wellesley11
- Plymouth10
- Hyannis9
- Needham8
- Newton8
- Braintree7
- Concord7
- Norwood7
- Quincy7
- Taunton7
Source: Doctors and Clinicians National Downloadable File (CMS)
Each Massachusetts primary care group profile shows the parent, sites, clinicians and identifiers
- Clinicians and specialtiesA count by specialty and a sample of the group's cliniciansOn every profile
- Practice locationsMain site and a sample of practice locations, with a count of the restOn every profile
- Medicare Part B paymentsMedicare payments to the group, from CMSOn every profile
- Group NPI and Medicare PAC IDIdentifiers for matching records across sourcesOn every profile
- Parent organizationThe health system, platform or owner above the groupOn every profile
- Every clinician and siteThe full roster and every practice locationWith a free account
- Leader and clinician contactsWork emails and mobile numbers, found on request and then validatedWith a free account
- EHR used by the group's cliniciansThe EHR in use at the group's sitesWith a free account
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Sources: Doctors and Clinicians National Downloadable File (CMS), Medicare Physician & Other Practitioners (CMS) and Dmand AI Org Hierarchy Data
Sources for the Massachusetts primary care group list
| Data on this page | Source |
|---|---|
| Medical groups, specialties and sites | Doctors and Clinicians National Downloadable File (CMS) and Dmand AI Professional Profile Data |
| Parent organizations and independence | Dmand AI Org Hierarchy Data |
| Physicians and HCPs | Dmand AI Affiliation Data |
| Group NPI and PAC ID | NPPES NPI Registry (CMS) and Doctors and Clinicians National Downloadable File (CMS) |
Data last refreshed October 2026Report an inaccuracyRemove my information
Groups whose main specialty is primary care and that have a Medicare PAC ID.
FAQ
Frequently asked questions about primary care groups in Massachusetts
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is the largest internal medicine group in Massachusetts?
Massachusetts General Physicians Organization (MGPO), based in Boston, with 1,331 internal medicine specialists and 5,784 HCPs. Massachusetts General Hospital is second with 1,290.
What is the largest nurse practitioner group in Massachusetts?
Walk-In MD Urgent Care, based in Randolph, with 15 nurse practitioner specialists and 21 HCPs. New Horizon Medical is second with 11.
How many primary care groups are in Massachusetts?
There are 677 primary care groups in Massachusetts with a Medicare PAC ID: 339 internal medicine, 200 nurse practitioner, 105 family medicine, 27 physician assistant, 3 clinical nurse specialist and 3 general practice. Between them they have 8,000 internal medicine specialists, 498 nurse practitioner specialists, 553 family physicians, 98 physician assistant specialists, 4 clinical nurse specialist specialists and 2 general practice specialists.
Which companies own the most primary care groups?
By physicians, Mass General Brigham, with 7,169 across 14 groups, followed by Beth Israel Lahey Health with 3,100 and UMass Memorial Health Care with 1,879.
How many Massachusetts primary care groups are independent?
411, or 61%, have no larger parent organization in the Dmand AI org hierarchy. 114 belong to a health system or hospital and 81 to a physician platform or corporate owner.
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