Jonathan Sylvan Williams, MD
Endocrinology, Diabetes & Metabolism Physician · Boston, MA
Jonathan Sylvan Williams, MD is an endocrinology, diabetes & metabolism physician with a practice address in Boston, Massachusetts, and NPI 1245297936, issued on Apr 27, 2006. Check the license (Massachusetts 204984, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- Jonathan Sylvan Williams
- Credential
- MD
- Primary taxonomy
- Endocrinology, Diabetes & Metabolism Physician 207RE0101X
- License number
- 204984 MA
Self-reported in NPPES; status is on the state search - Practice location
- 221 Longwood Avenue Rfb 2, Boston, MA 02115
- Phone
- (617) 732-5661
- Enumerated
- Apr 27, 2006
- Record last updated
- Apr 12, 2019 (not updated in 7 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20040623001479); accepts Medicare assignment
- Medical or professional school
- Hahnemann University College Of Medicine, 1998
- Entity
- Type 1 · individual
8 nearest endocrinology, diabetes & metabolism physician records → All 522 in Massachusetts → Look up another NPI →
Verify Jonathan Sylvan Williams in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
Search for license 204984Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Bills Medicare through one group practice
- Brigham And Womens Physicians Organization IncBoston, MA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Jonathan Sylvan Williams among 522 endocrinology, diabetes & metabolism physician records in Massachusetts
Jonathan Sylvan Williams, MD is one of 522 endocrinology, diabetes & metabolism physician records with a practice address in Massachusetts. 82% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 14% of them.
- NPI issued2006 · 14% of these records are older, 52% newer
- In a Medicare fileYes · 82% of these records are
- In the CMS Doctors and Clinicians fileYes · 72% of these records are
- Graduated1998 · median 2002 among the 378 with a school on file
- Record last updated2019 · 60% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RE0101X and a Massachusetts practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Endocrinology, Diabetes & Metabolism Physician providers in Massachusetts
There are 522 endocrinology, diabetes & metabolism physician records in Massachusetts.
All 522 in Massachusetts → Every provider in Boston → Endocrinology, Diabetes & Metabolism Physician nationwide →
The 8 endocrinology, diabetes & metabolism physician records with the nearest ZIP codes
- Gail Adler, MD PHDBoston, MA 021151780675280
- Shehzad Basaria, MDBoston, MA 021151699730101
- Edward Brown, MDBoston, MA 021151871550137
- Margo Hudson, MDBoston, MA 021151922065242
- Ursula Kaiser, MDBoston, MA 021151053377374
- Nikheel Kolatkar, M.D.Boston, MA 021151396748463
- P Larsen, MDBoston, MA 021151700842952
- Meryl Leboff, MDBoston, MA 021151235106030
Common questions
What is Jonathan Sylvan Williams, MD's NPI number?
Jonathan Sylvan Williams, MD's National Provider Identifier (NPI) is 1245297936, issued on Apr 27, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Jonathan Sylvan Williams, MD located?
The NPPES record lists a practice address at 221 Longwood Avenue Rfb 2, Boston, MA, 02115. Phone: (617) 732-5661. Providers update this record themselves, so call before visiting.
How can I verify Jonathan Sylvan Williams, MD's license?
NPPES lists Massachusetts license number 204984, as entered by the provider. Search the Massachusetts Board of Registration in Medicine at https://findmydoctor.mass.gov/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.