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JONATHAN SYLVAN WILLIAMS MD
NPI 1245297936
Internal Medicine - Endocrinology, Diabetes & Metabolism in Boston, MA

Active since April 27, 2006PECOS EnrolledAccepts Medicare Assignment
221 LONGWOOD AVENUE RFB 2, BRIGHAM AND WOMENS HOSPITAL ENDOCRINOLOGY DIABETES AND, BOSTON, MA 02115(617) 732-5661 Get Directions Write a Review

NPPES record last updated: April 12, 2019. Verified against the NPPES registry weekly; last sync: October 25, 2026.

About Jonathan Sylvan Williams Md NPPES

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

JONATHAN SYLVAN WILLIAMS MD (NPI 1245297936) is an individual endocrinology, diabetes & metabolism provider in Boston, Massachusetts, licensed in Massachusetts (204984) and active in the NPI registry since April 2006. He is enrolled in Medicare PECOS, is affiliated with Brigham And Women's Hospital, and is a graduate of Hahnemann University College Of Medicine (1998).

NPPES Registry Identity

NPI1245297936
Entity TypeIndividualMale
Primary Taxonomy207RE0101X
Provider Legal NameJONATHAN SYLVAN WILLIAMSCredential: MD
Location Address221 LONGWOOD AVENUE RFB 2, BRIGHAM AND WOMENS HOSPITAL ENDOCRINOLOGY DIABETES ANDBoston, MA 02115
Mailing Address221 Longwood Avenue Rfb 2, Brigham And Womens Hospital Endocrinology Diabetes AndBoston, MA 02115 · (617) 732-5661
Phone(617) 732-5661
Sole ProprietorNo
Medical School CMSHahnemann University College Of MedicineGraduated 1998
Enumeration DateApril 27, 2006
Last NPPES UpdateApril 12, 2019
✔ NPI 1245297936 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyInternal Medicine · Endocrinology, Diabetes & MetabolismAllopathic & Osteopathic Physicians
Taxonomy Code207RE0101X
License✔ Licensed in MA · 204984
Definition
An internist who concentrates on disorders of the internal (endocrine) glands such as the thyroid and adrenal glands. This specialist also deals with disorders such as diabetes, metabolic and nutritional disorders, obesity, pituitary diseases and menstrual and sexual problems.
Also ListedInternal MedicineTaxonomy 207R00000X · License 204984 (MA)
221 LONGWOOD AVENUE RFB 2, Boston, MA 02115
Open in Google Maps ↗

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

Jonathan Sylvan Williams Md 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 ID8123003928
PECOS Enrollment IDI20040623001479
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

4

Medicare enrollment records show Jonathan Williams reassigns Medicare billing to 4 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Brigham & Womens Physicians Organization Inc
0.3 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
Steward Medical Group, Inc
4.6 mi
Specialist
9 GALEN ST
Watertown, MA 02472
  • Reassigned Medicare billing, Massachusetts enrollment
  • 1,103 clinicians in this Medicare group
NPI 1629398219 (615) 467-4474
Sound Physicians Of Massachusetts, Inc
13 mi
Internal Medicine
150 YORK ST
Stoughton, MA 02072
  • Reassigned Medicare billing, Massachusetts enrollment
  • 337 clinicians in this Medicare group
NPI 1245784446 (781) 344-0600
Sound Physicians Of Massachusetts II PC
18 mi
Internal Medicine
235 N PEARL ST
Brockton, MA 02301
  • Reassigned Medicare billing, Massachusetts enrollment
  • 173 clinicians in this Medicare group
NPI 1306376397 (615) 377-5658

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

Hospital Affiliations CMS Care Compare

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

Brigham And Women's Hospital

Acute Care Hospitals · Boston, MA
5/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number220110
Location75 Francis StreetBoston, MA 02115 · Suffolk County
Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 02115 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.

Medicare Quality Performance CMS QPP · MIPS

Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.

Reported Quality Measures

Care Plan
Percentage of patients aged 65 years and older who have an advance care plan or surrogate decision maker documented in the medical record that an advance care plan was discussed but the patient did not wish or was not able to name a surrogate decision maker…
79%48 patients4/55-star benchmark: 100%
Providers report different measures because they deliver different services; reporting more or less information is not a reflection of quality. Star ratings appear only where CMS assigned them.

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 Jonathan Williams's NPI number?

The NPI number for Jonathan Williams is 1245297936. It was assigned to this individual provider in the NPPES registry on April 27, 2006.

Where is Jonathan Williams located?

Jonathan Williams practices at 221 Longwood Avenue Rfb 2 Brigham And Womens Hospital Endocrinology Diabetes And, Boston, MA 02115. The listed phone number is (617) 732-5661.

What is Jonathan Williams's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Endocrinology, Diabetes & Metabolism, with taxonomy code 207RE0101X.

Is Jonathan Williams enrolled in Medicare?

Yes. Jonathan Williams 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 Jonathan Williams's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Jonathan Williams reassigns Medicare benefits to 4 organizations: Brigham & Womens Physicians Organization Inc (Boston, MA), Steward Medical Group, Inc (Watertown, MA), Sound Physicians Of Massachusetts, Inc (Stoughton, MA) and Sound Physicians Of Massachusetts II PC (Brockton, MA). 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 Jonathan Williams's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

What insurance does Jonathan Williams accept?

Health plans from Taro Health list Jonathan Williams 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 Jonathan Williams affiliated with any hospitals?

According to CMS data, Jonathan Williams is affiliated with Brigham And Women's Hospital.

When was this NPI record last updated?

The NPPES record for Jonathan Williams was last updated on April 12, 2019. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 7 years 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.