Justin Adam Mazzillo, M.D.
Emergency Medicine Physician · Keene, NH
Justin Adam Mazzillo, M.D. is an emergency medicine physician with a practice address in Keene, New Hampshire, and NPI 1487924304, issued on Jan 9, 2012. Check the license (New Hampshire 16046, as entered in NPPES) on the New Hampshire Board of Medicine; the Medicare figures below come from public CMS files.
- Name
- Justin Adam Mazzillo
- Credential
- M.D.
- Primary taxonomy
- Emergency Medicine Physician 207P00000X
- License numbers
- 16046 NH
P1670 TX
Self-reported in NPPES; status is on the state search - Practice location
- 590 Court St, Keene, NH 03431
- Phone
- (603) 354-5454
- Enumerated
- Jan 9, 2012
- Record last updated
- Aug 28, 2013 (not updated in 13 years: call before relying on the address or phone)
- Medicaid ID
- 3085790 NH
- Medicare enrollment
- Enrolled (PECOS I20151016000768); accepts Medicare assignment
- Medical or professional school
- State University Of New York At Buffalo School Of Medicine, 2010
- Entity
- Type 1 · individual
8 nearest emergency medicine physician records → All 351 in New Hampshire → Look up another NPI →
Also registered at 590 Court St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Matthew Anderson, M.D.Critical Care Medicine (Anesthesiology) Physician1790927168
- William Argie, PA-CMedical Physician Assistant1265519946
- Jeremy Arnold, M.D.Emergency Medicine Physician1174784557
- Payson Ayer-Dufner, PA-CPhysician Assistant1124424379
- Everett Bacon, MDEmergency Medicine Physician1669827143
- Samantha BarryFamily Nurse Practitioner1568004307
Verify Justin Adam Mazzillo in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersNew Hampshire Board of Medicine
Search for license 16046Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
81% fewer Medicare Part D claims than the average emergency medicine physician in 2024
44 Medicare Part D claims for 28 beneficiaries, against an average of 226 among the 54,106 providers of this specialty who prescribed in Part D.
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
- Emergency Associates - University OF RochesterRochester, NY
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Justin Adam Mazzillo among 351 emergency medicine physician records in New Hampshire
Justin Adam Mazzillo, M.D. is one of 351 emergency medicine physician records with a practice address in New Hampshire. 76% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2012, is newer than 64% of them.
- NPI issued2012 · 64% of these records are older, 32% newer
- In a Medicare fileYes · 76% of these records are
- In the CMS Doctors and Clinicians fileYes · 58% of these records are
- Graduated2010 · median 2011 among the 205 with a school on file
- Record last updated2013 · 62% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207P00000X and a New Hampshire practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
30 emergency medicine physician records list a practice address in Keene
They are 30 of the 1,482 NPPES records with a practice address in Keene, and 351 emergency medicine physician records in New Hampshire.
All 351 in New Hampshire → Every provider in Keene → Emergency Medicine Physician nationwide →
The 8 emergency medicine physician records with the nearest ZIP codes
- Jeremy Arnold, M.D.Keene, NH 034311174784557
- Jacques Blanchet, MDKeene, NH 034311619046489
- Steven Boutrus, M.D.Keene, NH 034311346568110
- Thomas Cochran, MDKeene, NH 034311093914715
- Alexis Cochran, M.D.Keene, NH 034311780883413
- John Curtis, MDKeene, NH 034311033151030
- Steven Friese, MDKeene, NH 034311447364567
- Thomas Hennigan, M.D.Keene, NH 034311144302118
Common questions
What is Justin Adam Mazzillo, M.D.'s NPI number?
Justin Adam Mazzillo, M.D.'s National Provider Identifier (NPI) is 1487924304, issued on Jan 9, 2012. An NPI identifies a provider in billing; it is not a license.
Where is Justin Adam Mazzillo, M.D. located?
The NPPES record lists a practice address at 590 Court St, Keene, NH, 03431. Phone: (603) 354-5454. Providers update this record themselves, so call before visiting.
How can I verify Justin Adam Mazzillo, M.D.'s license?
NPPES lists New Hampshire license number 16046, 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 Justin Adam Mazzillo, M.D. prescribe under Medicare Part D?
In 2024, Justin Adam Mazzillo, M.D. had 44 Medicare Part D claims for 28 beneficiaries; the average among emergency medicine physician prescribers was 226. 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.