Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

Jonathan Peter Nass, MD

Individual provider Internal Medicine Physician · NPI 1558587998

Jonathan Peter Nass, MD practises Gastroenterology in South Weymouth, Massachusetts. Graduated from Tulane University School of Medicine in 2005, 21 years ago. Practices with South Shore Medical Center, Inc, a 175-clinician group, accepts Medicare assignment and offers telehealth. Licensed in Louisiana, Massachusetts and Rhode Island.

Years since qualifying
21
Trained at
Tulane University School of Medicine
Licensed in
LA, MA, RI
In the registry since
2007
Specialties on file
3
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

1085 Main St
South Weymouth, MA 02190-1547
Phone: (781) 331-2922
Fax: (781) 335-5702
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Gastroenterology Physician (primary) Taxonomy 207RG0100X · Licence 252551 (MA)
Internal Medicine Physician Taxonomy 207R00000X · Licence LP00455 (RI)
Gastroenterology Physician Taxonomy 207RG0100X · Licence MD.202069 (LA)

Record details

NPI number1558587998
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedApril 17, 2007
Last updated in NPPESDecember 18, 2019
Certification dateDecember 18, 2019

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyGASTROENTEROLOGY
Medical schoolTULANE UNIVERSITY SCHOOL OF MEDICINE
Graduated 2005 (21 years in practice)
Group practice South Shore Medical Center, Inc. — 175 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services
Practice locations2 on file with Medicare

Procedures

From CMS Care Compare, which counts the procedures a clinician billed to Original Medicare and Medicare Advantage over a recent 12-month period. CMS reports a fixed list of common procedures, so this is not everything the clinician does. Counts of 10 or fewer are given as a range, because CMS withholds small numbers.

Colonoscopy 125 times · 85th percentile
Upper gastrointestinal (GI) endoscopy for acid reflux 112 times · 79th percentile

The percentile compares how often this clinician performed the procedure with other clinicians who performed it, as CMS calculates it. It measures volume, not outcomes or skill.

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients407
Services billed 755 a service is one billed item, such as a visit, a test or a procedure
Average patient age73

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $31 1 payment · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

Colleagues at South Shore Medical Center, Inc

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 175 clinicians in the practice; 12 are shown here.

Other providers in South Weymouth