Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
NPIDirectory

Dr. Gregory Maurice Marcus, MD

Individual provider Internal Medicine Physician · NPI 1891720579

Dr. Gregory Maurice Marcus, MD is registered under Cardiovascular Disease (Cardiology) in San Francisco, California. Graduated from George Washington University School of Medicine in 1998, 28 years ago. Practices with UCSF Medical Group Business Services, a 1,531-clinician group, accepts Medicare assignment and offers telehealth. Licensed in California.

Years since qualifying
28
Trained at
George Washington University School of Medicine
Licensed in
CA
In the registry since
2006
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

505 Parnassus Ave
San Francisco, CA 94143-2204
Phone: (415) 353-8870
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Clinical Cardiac Electrophysiology Physician (primary) Taxonomy 207RC0001X · Licence A69390 (CA)
Internal Medicine Physician Taxonomy 207R00000X · Licence A69390 (CA)
Cardiovascular Disease Physician Taxonomy 207RC0000X · Licence A69390 (CA)

Record details

NPI number1891720579
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJuly 11, 2006
Last updated in NPPESApril 24, 2017

Medicare enrollment

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

Medicare specialtyCARDIOVASCULAR DISEASE (CARDIOLOGY)
Also practisesINTERNAL MEDICINE
Medical schoolGEORGE WASHINGTON UNIVERSITY SCHOOL OF MEDICINE
Graduated 1998 (28 years in practice)
Group practice Ucsf Medical Group Business Services — 1531 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services
Practice locations3 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.

Pacemaker insertion or repair 1–10 times

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 patients669
Services billed 1,556 a service is one billed item, such as a visit, a test or a procedure
Average patient age75

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 $98 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 UCSF Medical Group Business Services

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 1531 clinicians in the practice; 12 are shown here.

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