William Belcastro, M.D.
Internal Medicine Physician · Springfield, MA
William Belcastro, M.D. is an internal medicine physician with a practice address in Springfield, Massachusetts, and NPI 1548269251, issued on Jul 15, 2005. Check the license (Massachusetts 37640, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- William Belcastro
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 37640 MA
Self-reported in NPPES; status is on the state search - Practice location
- 299 Carew St, Springfield, MA 01104
- Phone
- (413) 737-2371
- Enumerated
- Jul 15, 2005
- Entity
- Type 1 · individual
Also registered at 299 Carew St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify William Belcastro in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
Search for license 37640Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS, AOA, NCCPA, AANPNot checked
39% more Medicare Part D claims than the average internal medicine physician in 2024
4,402 Medicare Part D claims for 352 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 12% of claims. 50 claims were for opioids.
Most prescribed
- Atorvastatin Calcium417 claims
- Losartan Potassium281 claims
- Amlodipine Besylate225 claims
- Metoprolol Succinate190 claims
- Hydrochlorothiazide184 claims
- Lisinopril176 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.
Industry payments in 2024: $33.88
2 payments, mostly food and beverage; the largest payer was Lilly USA, LLC. The 50,334 providers of this specialty with any payment received $1,303.06 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
282 internal medicine physician records list a Springfield practice address
They are 282 of the 8,553 NPPES records with a Springfield practice address, and 6,825 internal medicine physician records in Massachusetts.
All 282 in Springfield → All 6,825 in Massachusetts → Every provider in Springfield →
Other internal medicine physician records in Massachusetts
- Nawal Aamir, MDWorcester, MA1588248926
- Nathan Abare, MDSpringfield, MA1386852747
- Nooshin Abbasi, MD MPHNewton, MA1831888353
- Taimur AbbasiBoston, MA1841673522
- Lauren Abbate, MDBoston, MA1922099621
- Bassima Abdallah, MDBoston, MA1912327305
- Maya Abdallah, MDBoston, MA1861854937
- Samah Abdallah, MDBrighton, MA1730814971
- Omar Abdel-Wahab, M.D.Boston, MA1023042777
- Mohab AbdelhalimBoston, MA1871388496
Common questions
What is William Belcastro, M.D.'s NPI number?
William Belcastro, M.D.'s National Provider Identifier (NPI) is 1548269251, issued on Jul 15, 2005. An NPI identifies a provider in billing; it is not a license.
Where is William Belcastro, M.D. located?
The NPPES record lists a practice address at 299 Carew St, Springfield, MA, 01104. Phone: (413) 737-2371. Providers update this record themselves, so call before visiting.
How can I verify William Belcastro, M.D.'s license?
NPPES lists Massachusetts license number 37640, as entered by the provider. Search the Massachusetts Board of Registration in Medicine at https://www.mass.gov/orgs/board-of-registration-in-medicine. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does William Belcastro, M.D. prescribe under Medicare Part D?
In 2024, William Belcastro, M.D. had 4,402 Medicare Part D claims for 352 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), loaded Aug 27, 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) 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 27, 2026.