Robert J. Master, MD
Internal Medicine Physician · Cambridge, MA
Robert J. Master, MD is an internal medicine physician with a practice address in Cambridge, Massachusetts, and NPI 1518048131, issued on Oct 18, 2006. Check the license (Massachusetts 35355, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- Robert J. Master
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 35355 MA
Self-reported in NPPES; status is on the state search - Practice location
- 9A Forest St, Cambridge, MA 02140
- Phone
- (617) 680-6892
- Enumerated
- Oct 18, 2006
- Record last updated
- Sep 17, 2024
- Fax
- (857) 678-4049
- Medicaid ID
- 0138401 MA
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 6,825 in Massachusetts → Look up another NPI →
Verify Robert J. Master in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
Search for license 35355Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
46% fewer Medicare Part D claims than the average internal medicine physician in 2024
1,718 Medicare Part D claims for 57 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 7% of claims. 40 claims were for opioids.
Most prescribed
- Atorvastatin Calcium94 claims
- Amlodipine Besylate79 claims
- Levothyroxine Sodium74 claims
- Gabapentin70 claims
- Tamsulosin Hcl59 claims
- Omeprazole58 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.
Robert J. Master among 6,825 internal medicine physician records in Massachusetts
Robert J. Master, MD is one of 6,825 internal medicine physician records with a practice address in Massachusetts. 75% 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 12% of them.
- NPI issued2006 · 12% of these records are older, 54% newer
- In a Medicare fileYes · 75% of these records are
- In the CMS Doctors and Clinicians fileNo · 60% of these records are
- Record last updated2024 · 64% 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 Massachusetts practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
300 internal medicine physician records list a practice address in Cambridge
They are 300 of the 5,145 NPPES records with a practice address in Cambridge, and 6,825 internal medicine physician records in Massachusetts.
All 6,825 in Massachusetts → Every provider in Cambridge → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Emily Chen, M.D.Cambridge, MA 021401013336536
- Cindy Chen, M.D.Cambridge, MA 021401417342627
- Bruce Ditzion, M.D.Cambridge, MA 021401346365269
- Anna Ham, DOCambridge, MA 021401740355981
- Brian Pereira, M.D.Cambridge, MA 021401881793198
- Guy Pugh, M.D.Cambridge, MA 021401154378818
- Edward Shashoua, D.O.Cambridge, MA 021401811916802
- Jacqueline Spencer, M.D.Cambridge, MA 021401851482418
Common questions
What is Robert J. Master, MD's NPI number?
Robert J. Master, MD's National Provider Identifier (NPI) is 1518048131, issued on Oct 18, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Robert J. Master, MD located?
The NPPES record lists a practice address at 9A Forest St, Cambridge, MA, 02140. Phone: (617) 680-6892. Providers update this record themselves, so call before visiting.
How can I verify Robert J. Master, MD's license?
NPPES lists Massachusetts license number 35355, 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.
How much does Robert J. Master, MD prescribe under Medicare Part D?
In 2024, Robert J. Master, MD had 1,718 Medicare Part D claims for 57 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.