William J. Kassler, MD
Internal Medicine Physician · Manchester, NH
William J. Kassler, MD is an internal medicine physician with a practice address in Manchester, New Hampshire, and NPI 1538162672, issued on May 23, 2005. Check the license (New Hampshire 10716, as entered in NPPES) on the New Hampshire Board of Medicine; the Medicare figures below come from public CMS files.
- Name
- William J. Kassler
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 10716 NH
Self-reported in NPPES; status is on the state search - Practice location
- 1415 Elm St, Manchester, NH 03101
- Phone
- (603) 626-9500
- Enumerated
- May 23, 2005
- Record last updated
- Dec 4, 2013 (not updated in 13 years: call before relying on the address or phone)
- Fax
- (603) 626-0899
- Medicaid ID
- 030201969 NH
- Medicare enrollment
- Enrolled (PECOS I20150608000598); accepts Medicare assignment
- Medical or professional school
- University Of Massachusetts Medical School, 1984
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 673 in New Hampshire → Look up another NPI →
Also registered at 1415 Elm St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify William J. Kassler in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersNew Hampshire Board of Medicine
Search for license 10716Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
93% fewer Medicare Part D claims than the average internal medicine physician in 2024
228 Medicare Part D claims for 46 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Most prescribed
- Metformin Hcl17 claims
- Amlodipine Besylate15 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Bills Medicare through one group practice
- Amoskeag HealthManchester, NH
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
William J. Kassler among 673 internal medicine physician records in New Hampshire
William J. Kassler, MD is one of 673 internal medicine physician records with a practice address in New Hampshire. 81% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2005, is newer than 0% of them.
- NPI issued2005 · 0% of these records are older, 92% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileYes · 66% of these records are
- Graduated1984 · median 2005 among the 443 with a school on file
- Record last updated2013 · 53% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a New Hampshire practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
95 internal medicine physician records list a practice address in Manchester
They are 95 of the 4,401 NPPES records with a practice address in Manchester, and 673 internal medicine physician records in New Hampshire.
All 673 in New Hampshire → Every provider in Manchester → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Genesio Biesek, M.D.Manchester, NH 031011518943711
- Deborah Biron, M.D.Manchester, NH 031021952389108
- Charles Carrier, MDManchester, NH 031021932136017
- Judith Devine, M.D.Manchester, NH 031021427152768
- Nonso Egbuonu, M.DManchester, NH 031021558689349
- Mark Ferlan, DOManchester, NH 031021124230370
- Scott Leblanc, D.O.Manchester, NH 031021841235827
- Ovidiu Lungulescu, M.D.Manchester, NH 031021851573851
Common questions
What is William J. Kassler, MD's NPI number?
William J. Kassler, MD's National Provider Identifier (NPI) is 1538162672, issued on May 23, 2005. An NPI identifies a provider in billing; it is not a license.
Where is William J. Kassler, MD located?
The NPPES record lists a practice address at 1415 Elm St, Manchester, NH, 03101. Phone: (603) 626-9500. Providers update this record themselves, so call before visiting.
How can I verify William J. Kassler, MD's license?
NPPES lists New Hampshire license number 10716, as entered by the provider. Search the New Hampshire Board of Medicine at https://www.oplc.nh.gov/board-medicine. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does William J. Kassler, MD prescribe under Medicare Part D?
In 2024, William J. Kassler, MD had 228 Medicare Part D claims for 46 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
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.