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DR. EVAN WILLIAM GWYN M.D.
NPI 1154558500
Internal Medicine in Boston, MA

Active since June 12, 2009PECOS EnrolledAccepts Medicare Assignment
55 FRUIT STREET, HOSPITAL MEDICINE UNIT, BLAKE 1500, BOSTON, MA 02114(617) 724-3874(617) 724-9428 Get Directions Write a Review

NPPES record last updated: December 29, 2025. Verified against the NPPES registry weekly; last sync: November 01, 2026.

Record update history: Dec 29, 2025, Nov 20, 2022 (2 updates tracked since 2022).

About Dr. Evan William Gwyn M.d. NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

DR. EVAN WILLIAM GWYN M.D. (NPI 1154558500) is an individual internal medicine provider in Boston, Massachusetts, licensed in Massachusetts (240175) and active in the NPI registry since June 2009. He is enrolled in Medicare PECOS, is affiliated with Massachusetts General Hospital, and maintains 3 additional practice locations.

NPPES Registry Identity

NPI1154558500
Entity TypeIndividualMale
Primary Taxonomy207R00000X
Provider Legal NameDR. EVAN WILLIAM GWYNCredential: M.D.
Location Address55 FRUIT STREET, HOSPITAL MEDICINE UNIT, BLAKE 1500Boston, MA 02114
Mailing Address330 Brookline Ave, Span 2Boston, MA 02215 · (617) 794-1338
Phone(617) 724-3874
Fax(617) 724-9428
Sole ProprietorNo
Medical School CMSOtherGraduated 2009
Enumeration DateJune 12, 2009
Last NPPES UpdateDecember 29, 20252 updates tracked since enumeration
NPPES CertifiedDecember 29, 2025
✔ NPI 1154558500 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207R00000X
License✔ Licensed in MA · 240175
Definition
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
55 FRUIT STREET, Boston, MA 02114
Open in Google Maps ↗

Secondary Practice Locations 3

Location 11153 Centre StJamaica Plain, MA 02130-3446 · Phone (617) 983-7000
Location 2330 Brookline Ave, Deaconess 311Boston, MA 02215-5400 · Phone (504) 669-3411
Location 375 Francis StBoston, MA 02115-6110 · Phone (617) 732-5500

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Taro Health.Insurance ›

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Dr. Evan William Gwyn M.d. is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID8527216217
PECOS Enrollment IDI20120921000692
Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignments

6

Medicare enrollment records show Evan Gwyn reassigns Medicare billing to 6 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Massachusetts General Physicians Organization Inc
Same address
Dermatology
55 FRUIT ST, BUL 2
Boston, MA 02114
  • Reassigned Medicare billing, Massachusetts enrollment
  • 6,360 clinicians in this Medicare group
NPI 1801874573 (617) 724-0287
The General Hospital Corporation
Same address
General Acute Care Hospital
55 FRUIT ST, BULFINCH 360
Boston, MA 02114
  • Reassigned Medicare billing, Massachusetts enrollment
  • 6,234 clinicians in this Medicare group
NPI 1023049236 (617) 726-2000
Associated Physicians Of Harvard Medical Faculty Physicians At Beth Is
2.5 mi
Internal Medicine
330 BROOKLINE AVE, HOSPITALIST PROGRAM, PBS 2
Boston, MA 02215
  • Reassigned Medicare billing, Massachusetts enrollment
  • 346 clinicians in this Medicare group
NPI 1497151773 (617) 754-4667
Beth Israel Deaconess Medical Center, Inc.
2.5 mi
General Acute Care Hospital
330 BROOKLINE AVE, ST 207
Boston, MA 02215
  • Reassigned Medicare billing, Massachusetts enrollment
  • 1,477 clinicians in this Medicare group
NPI 1548202641 (617) 667-1961
Harvard Medical Faculty Phys At Beth Israel Deaconess Med Ctr Inc
2.5 mi
Internal Medicine
330 BROOKLINE AVE
Boston, MA 02215
  • Reassigned Medicare billing, Massachusetts enrollment
  • 2,579 clinicians in this Medicare group
NPI 1194765438 (617) 754-9600
Brigham & Womens Physicians Organization Inc
2.7 mi
Internal Medicine
75 FRANCIS ST
Boston, MA 02115
  • Reassigned Medicare billing, Massachusetts enrollment
  • 4,574 clinicians in this Medicare group
NPI 1033535497 (617) 732-5500

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Areas of Expertise CMS Part B claims 2

Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.

Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes 99232
Follow-up hospital inpatient care involves daily check-ups while you're admitted in the hospital. Typically, a healthcare provider spends about 25 minutes each day reviewing your condition, adjusting treatment if needed, and answering any questions you might have.
62 services20 patients
Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes 99233
Follow-up hospital inpatient care per day typically involves a 35-minute check-up by your healthcare provider. This service includes monitoring your health progress, adjusting your treatment plan if needed, and answering any questions you may have about your condition or care.
34 services25 patients

Hospital Affiliations CMS Care Compare

Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.

Massachusetts General Hospital

Acute Care Hospitals · Boston, MA
5/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number220071
Location55 Fruit StreetBoston, MA 02114 · Suffolk County
Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 02114 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$144.11 typical visit price
range $63.72 – $189.86
Typical copayment $36.02 (range $15.93 – $47.46)
Most-billed visit code 99204
Established Patient
$111.18 typical visit price
range $21.07 – $155.29
Typical copayment $27.79 (range $5.26 – $38.82)
Most-billed visit code 99214
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

KUI TOH GERARD LEONG M.D.
Internal Medicine (Cardiovascular Disease)
55 FRUIT STREET, MASSACHUSETTS GENERAL HOSPITAL
BOSTON, MA 02114
Suffolk County (617) 726-8862
MS. JACQUELINE BANGO LICSW
Social Worker (Clinical)
55 FRUIT STREET, FOUNDERS BUILDING SUITE 880
BOSTON, MA 02114
Suffolk County (617) 643-8281
SARA ELIZABETH GROSSLEIN PA
Physician Assistant
55 FRUIT STREET, WHITE 1
BOSTON, MA 02114
Suffolk County (617) 724-4100
JEFFREY M ELLENBOGEN M.D.
Psychiatry & Neurology (Neurology)
55 FRUIT STREET, WANG 720 (NEUROLOGY)
BOSTON, MA 02114
Suffolk County (617) 724-7419
DR. NANCY LEE HARRIS MD
Pathology (Anatomic Pathology & Clinical Pathology)
55 FRUIT STREET, WRN 2 PATHOLOGY ASSOCIATES
BOSTON, MA 02114
Suffolk County (617) 726-5155
DR. STANLEY YANG SHAW MD PHD
Internal Medicine (Cardiovascular Disease)
55 FRUIT STREET, YAW 5 CARDIAC UNIT ASSOCIATES
BOSTON, MA 02114
Suffolk County (617) 724-6750
LEONARDO V RIELLA M.D., PHD
Internal Medicine
55 FRUIT STREET, WHITE 5
BOSTON, MA 02114
Suffolk County (617) 726-5050
SUSAN MAHER CRNA
Nurse Anesthetist, Certified Registered
55 FRUIT STREET, CLN 309 MGH ANESTHESIA ASSOCIATES
BOSTON, MA 02114
Suffolk County (617) 726-3030

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Evan Gwyn's NPI number?

The NPI number for Evan Gwyn is 1154558500. It was assigned to this individual provider in the NPPES registry on June 12, 2009.

Where is Evan Gwyn located?

Evan Gwyn practices at 55 Fruit Street Hospital Medicine Unit, Blake 1500, Boston, MA 02114. The listed phone number is (617) 724-3874.

What is Evan Gwyn's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Is Evan Gwyn enrolled in Medicare?

Yes. Evan Gwyn is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

Which organizations bill Medicare for Evan Gwyn's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Evan Gwyn reassigns Medicare benefits to 6 organizations: Massachusetts General Physicians Organization Inc (Boston, MA), The General Hospital Corporation (Boston, MA), Associated Physicians Of Harvard Medical Faculty Physicians At Beth Is (Boston, MA), Beth Israel Deaconess Medical Center, Inc. (Boston, MA), Harvard Medical Faculty Phys At Beth Israel Deaconess Med Ctr Inc (Boston, MA) and 1 more organization, listed in the Medicare section above. Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Evan Gwyn's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

What insurance does Evan Gwyn accept?

Health plans from Taro Health list Evan Gwyn as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.

Is Evan Gwyn affiliated with any hospitals?

According to CMS data, Evan Gwyn is affiliated with Massachusetts General Hospital.

When was this NPI record last updated?

The NPPES record for Evan Gwyn was last updated on December 29, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.