Thomas Patrick O'Connor, M.D.
Internal Medicine Physician · Weymouth, MA
Thomas Patrick O'Connor, M.D. is an internal medicine physician with a practice address in Weymouth, Massachusetts, and NPI 1669507141, issued on Feb 23, 2007. Check the license (Massachusetts 231774, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- Thomas Patrick O'Connor
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License numbers
- 231774 MA
MD035011 DC
Self-reported in NPPES; status is on the state search - Practice location
- 51 Performance Dr, Weymouth, MA 02189
- Phone
- (781) 337-9091
- Enumerated
- Feb 23, 2007
- Record last updated
- Jan 21, 2014 (not updated in 12 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20070731000287); accepts Medicare assignment
- Medical or professional school
- State University Of New York At Buffalo School Of Medicine, 2001
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 6,825 in Massachusetts → Look up another NPI →
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A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Thomas Patrick O'Connor in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
Search for license 231774Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
26% fewer Medicare Part D claims than the average internal medicine physician in 2024
2,355 Medicare Part D claims for 337 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 20% of claims. 246 claims were for opioids.
Most prescribed
- Prednisone239 claims
- Abiraterone Acetate194 claims
- Letrozole131 claims
- Ondansetron Hcl116 claims
- Oxycodone Hcl97 claims
- Bicalutamide94 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.
The practice group's MIPS final score for 2023 (Medicare payment program): 86.3 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Bills Medicare through one group practice
- Dana-Farber Cancer Institute, Inc.Boston, MA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Thomas Patrick O'Connor among 6,825 internal medicine physician records in Massachusetts
Thomas Patrick O'Connor, M.D. 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 2007, is newer than 46% of them.
- NPI issued2007 · 46% of these records are older, 45% newer
- In a Medicare fileYes · 75% of these records are
- In the CMS Doctors and Clinicians fileYes · 60% of these records are
- Graduated2001 · median 2004 among the 4,103 with a school on file
- Record last updated2014 · 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).
23 internal medicine physician records list a practice address in Weymouth
They are 23 of the 1,156 NPPES records with a practice address in Weymouth, and 6,825 internal medicine physician records in Massachusetts.
All 6,825 in Massachusetts → Every provider in Weymouth → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Aboualkheir Alzaim, MDSouth Weymouth, MA 021901073595260
- Brian Battista, MDSouth Weymouth, MA 021901821075961
- Charles Chalko, D.O.South Weymouth, MA 021901548218126
- Brian Dolan, M.D.Weymouth, MA 021901952345928
- Judy Dunal, MDSouth Weymouth, MA 021901619954757
- Vitaly Ermolin, MDWeymouth, MA 021901114901485
- Robert Lille, MDSouth Weymouth, MA 021901548247695
- Marvin Lipschutz, M.D.Weymouth, MA 021901821060484
Common questions
What is Thomas Patrick O'Connor, M.D.'s NPI number?
Thomas Patrick O'Connor, M.D.'s National Provider Identifier (NPI) is 1669507141, issued on Feb 23, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Thomas Patrick O'Connor, M.D. located?
The NPPES record lists a practice address at 51 Performance Dr, Weymouth, MA, 02189. Phone: (781) 337-9091. Providers update this record themselves, so call before visiting.
How can I verify Thomas Patrick O'Connor, M.D.'s license?
NPPES lists Massachusetts license number 231774, 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 Thomas Patrick O'Connor, M.D. prescribe under Medicare Part D?
In 2024, Thomas Patrick O'Connor, M.D. had 2,355 Medicare Part D claims for 337 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
What is Thomas Patrick O'Connor, M.D.'s MIPS final score?
The 2023 MIPS final score is 86.3 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
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.