Updated October 2026

Medical groups in Massachusetts

Medical group directory
Massachusetts

Medical groups: 2,293
Multi-specialty: 430
Single-specialty: 1,863
More than one site: 1,166
100+ physicians: 73

There are 2,293 medical groups in Massachusetts with a Medicare PAC ID. Massachusetts General Physicians Organization (MGPO) is the largest, with 3,803 Massachusetts physicians. Mass General Brigham has the most physicians across its groups, 7,818, and 70% of Massachusetts groups are independent.

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Massachusetts General Physicians Organization (MGPO) is the largest medical 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. 73 Massachusetts groups have 100 or more physicians.

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Medical groups in Massachusetts, ranked by physicians
#	Medical group	Parent organization	Physicians	HCPs	Decision makers
1	Massachusetts General Physicians Organization (MGPO)Boston · 296 sites	Parent on file	3,803	5,784	Decision makers
2	Massachusetts General HospitalBoston · 124 sites	Parent on file	3,723	5,645	Decision makers
3	Brigham and Women's HospitalBoston · 203 sites	Parent on file	3,175	4,508	Decision makers
4	Harvard Medical Faculty Physicians at Beth Israel Deaconess Medical Center (HMFP)Boston · 147 sites	Parent on file	2,055	2,817	Decision makers
5	UMass Memorial Medical GroupWorcester · 166 sites	Parent on file	1,850	3,037	Decision makers
6	Steward Medical GroupWatertown · 269 sites	Parent on file	1,339	2,098	Decision makers
7	Lahey ClinicBurlington · 116 sites	Parent on file	1,144	1,915	Decision makers
8	Beth Israel Deaconess Medical CenterBoston · 48 sites	Parent on file	1,060	1,334	Decision makers
9	Boston Children's HospitalBoston · 32 sites	Parent on file	982	1,361	Decision makers
10	Baystate Medical PracticesSpringfield · 85 sites	Parent on file	965	1,610	Decision makers
11	Harvard Medical Faculty Physicians at Beth Israel Deaconess Medical CenterBoston · 88 sites	Parent on file	939	1,318	Decision makers
12	Binney Medical GroupBoston · 35 sites	Parent on file	768	1,165	Decision makers
13	Atrius HealthAuburndale · 101 sites	Parent on file	765	1,577	Decision makers
14	Mass General Brigham Medical GroupSomerville · 70 sites	Parent on file	669	1,055	Decision makers
15	Cambridge Health AllianceCambridge · 29 sites	Parent on file	636	1,126	Decision makers
16	Mass General Brigham (formerly North Shore Physicians Group)Somerville · 88 sites	Parent on file	588	1,049	Decision makers
17	Southcoast HealthFairhaven · 92 sites	Parent on file	568	1,146	Decision makers
18	Boston Medical Center (BMC)Boston · 42 sites	Parent on file	524	738	Decision makers
19	Boston University Medical Group (Boston University Internal Medicine Associates)Boston · 22 sites	Parent on file	474	638	Decision makers
20	Cape Cod HealthcareHyannis · 37 sites	Parent on file	385	565	Decision makers
21	Reliant Medical GroupWorcesteer · 46 sites	Parent on file	376	820	Decision makers
22	Coastal Medical AssociatesWeymouth · 49 sites	Parent on file	369	753	Decision makers
23	Mass General Brigham Community Physicians OrganizationSomerville · 95 sites	Parent on file	341	576	Decision makers
24	Mass General Brigham Medical Group Western MassachusettsSomerville · 46 sites	Parent on file	333	529	Decision makers
25	Mass Eye and EarQuincy · 33 sites	Parent on file	315	437	Decision makers
26	Harbor Medical AssociatesSouth Weymouth · 25 sites	Parent on file	304	382	Decision makers
27	Emerson HealthConcord · 40 sites	Parent on file	303	444	Decision makers
28	Mount Auburn Professional ServicesCambridge · 31 sites	Parent on file	300	462	Decision makers
29	Beth Israel Lahey HealthCambridge · 43 sites	Parent on file	280	496	Decision makers
30	Pratt Medical Group, Inc. - General Medical Associates (General Internal Medicine)Boston · 23 sites	Parent on file	264	412	Decision makers
31	Signature Medical GroupBrockton · 42 sites	Parent on file	258	439	Decision makers
32	Internal Medical Associates-EbnhcEast Boston · 34 sites	Parent on file	255	520	Decision makers
33	Lahey ClinicBurlington · 53 sites	Parent on file	248	430	Decision makers
34	Medical Affiliates of Cape Cod (MACC)Hyannis · 47 sites	Parent on file	247	417	Decision makers
35	Beth Israel Deaconess HealthcareNeedham · 76 sites	Parent on file	245	405	Decision makers
36	NeighborHealthEast Boston · 31 sites	Parent on file	234	468	Decision makers
37	McLean HospitalBelmont · 4 sites	Parent on file	210	362	Decision makers
38	Berkshire Faculty ServicesPittsfield · 37 sites	Parent on file	202	397	Decision makers
39	Heywood HospitalGardner · 6 sites	Parent on file	199	315	Decision makers
40	Sound PhysiciansNorth Adams · 27 sites	Parent on file	196	268	Decision makers
41	Nashoba Valley Medical CenterAyer · 48 sites	Parent on file	193	319	Decision makers
42	Boston Children's Hospital Department of Anesthesiology, Critical Care and Pain MedicineBoston · 11 sites	Parent on file	193	274	Decision makers
43	Merrimack Health Community Medical Associates (CMA)Lawrence · 23 sites	Parent on file	189	250	Decision makers
44	Athol HospitalGardner · 2 sites	Parent on file	185	310	Decision makers
45	Merrimack Health Lawrence HospitalLawrence · 10 sites	Parent on file	185	244	Decision makers
46	Martha's Vineyard HospitalOak Bluffs · 2 sites	Parent on file	182	257	Decision makers
47	Berkshire Medical CenterPittsfield · 10 sites	Parent on file	181	350	Decision makers
48	Trinity Health Of New England Medical GroupSpringfield · 38 sites	Parent on file	174	346	Decision makers
49	South Shore Medical CenterNorwell · 35 sites	Parent on file	169	408	Decision makers
50	Pratt Pediatric AssociatesBoston · 12 sites	Parent on file	169	193	Decision makers

Showing 1 to 10 of 2,293 medical groups in Massachusetts

Sources: Doctors and Clinicians National Downloadable File (CMS) and Dmand AI Affiliation Data

Mass General Brigham has the most physicians in Massachusetts medical groups, with 7,818 across 30 groups

Dmand AI maps every medical group to its parent organization, up to the health system or platform at the top. 69 parent organizations have two or more Massachusetts medical groups. Among health systems, Tufts Medicine has the most groups, 31. Each clinician counts once per parent organization.

Parent organizations with the most Massachusetts medical groups
#	Parent organization	Massachusetts groups	Physicians	HCPs
1	Mass General BrighamHealth system	30	7,818	12,493
2	Beth Israel Lahey HealthHealth system	26	3,175	4,952
3	UMass Memorial Health CareHealth system	7	1,898	3,218
4	The Children's HospitalHealth system	18	1,676	2,584
5	Beth Israel Lahey HealthHealth system	10	1,442	2,536
6	Bookmark MedicalPhysician practice platform	2	1,347	2,124
7	Tufts MedicineHealth system	31	1,344	2,232
8	UnitedHealth GroupDiversified health company	3	1,097	2,341
9	Boston UniversityAcademic health system	12	914	1,527
10	Boston Medical Center Health SystemHealth system	13	855	1,228

Top 10 of 69 parent organizations with two or more Massachusetts groups

Mass General BrighamHealth system · 30 Massachusetts medical groups
Massachusetts General Physicians Organization (MGPO)Multi-specialty group · Boston
Massachusetts General HospitalMulti-specialty group · Boston
28 more Massachusetts groups and their practice sites

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Source: Dmand AI Org Hierarchy Data

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Dmand AI maps the owners, administrators and physician leaders at each of the 2,293 Massachusetts medical groups, with the parent organization above each one, and finds validated work emails and mobile numbers.

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70% of Massachusetts medical 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 medical groups by ownership

Independent1,60270%
Health system or hospital26712%
Platform or corporate owner22110%
Community or government1165%
Other organization874%

Source: Dmand AI Org Hierarchy Data

454 Massachusetts medical groups practice at a hospital site

Beyond their own offices, groups practice at the sites of care linked to them in the org hierarchy. A group can practice at several kinds of site, so the shares overlap.

Sources: Dmand AI Practice Data and Dmand AI Org Hierarchy Data

Primary care groups are the most common medical groups in Massachusetts, with 677

Each group is counted once, under its main specialty. Behavioral and mental health groups are second, with 433, and 430 Massachusetts groups are multi-specialty.

Source: Dmand AI Professional Profile Data

55,419 Massachusetts HCPs work in Massachusetts medical groups, 25,246 of them physicians

Each clinician is counted once, across every Massachusetts group they are linked to. Only clinicians with a Massachusetts address are counted.

HCPs in Massachusetts medical groups by type

Physicians (MD, DO)25,24646%
Nurses and nurse practitioners11,19120%
Behavioral health clinicians8,47415%
Physician assistants4,7339%
Therapists (PT and OT)2,4514%
Other HCPs3,3246%

Source: Dmand AI Affiliation Data

Boston has the most medical groups in Massachusetts, with 158

158medical groups in Boston 79medical groups in Springfield 72medical groups in Worcester 51medical groups in Framingham 45medical groups in Fall River 42medical groups in Brockton

More Massachusetts cities with medical groups

Source: Doctors and Clinicians National Downloadable File (CMS)

Each Massachusetts medical 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

Free account: 30 days free, self-serve, no credit card.

Sources: Doctors and Clinicians National Downloadable File (CMS), Medicare Physician & Other Practitioners (CMS) and Dmand AI Org Hierarchy Data

Sources for the Massachusetts medical group directory

Sources for the data on this page
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 inaccuracy Remove my information

The directory lists groups with a Medicare PAC ID.

FAQ

Frequently asked questions about medical 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.

How many medical groups are in Massachusetts?

There are 2,293 medical groups in Massachusetts with a Medicare PAC ID: 430 multi-specialty and 1,863 single-specialty.

What is the largest medical group in Massachusetts?

Massachusetts General Physicians Organization (MGPO) in Boston, with 3,803 physicians and 5,784 HCPs with a Massachusetts address. Massachusetts General Hospital is second with 3,723, and Brigham and Women's Hospital is third with 3,175.

Which health system has the most medical groups in Massachusetts?

By physicians, Mass General Brigham, with 7,818 across 30 groups, followed by Beth Israel Lahey Health with 3,175 and UMass Memorial Health Care with 1,898.

How many Massachusetts medical groups are independent?

1,602, or 70%, have no larger parent organization in the Dmand AI org hierarchy. 267 belong to a health system or hospital and 221 to a physician platform or corporate owner.

How many Massachusetts medical groups practice at a hospital?

454 Massachusetts groups practice at a hospital site linked to them in the Dmand AI org hierarchy.

How do I find a medical group's NPI or PAC ID?

Each medical group profile lists the group NPI and Medicare PAC ID at the top, with the main address and phone number. The NPI comes from the NPPES NPI Registry and the PAC ID from CMS Medicare enrollment.

How do I find decision makers at Massachusetts medical groups?

Open a group's profile for its parent organization and leaders, then get work emails and mobile numbers through Dmand AI's healthcare waterfall enrichment. 30 days free, self-serve, no credit card.

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