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

Mark D Weissig, MD

Individual provider Internal Medicine Physician · NPI 1649266032

Mark D Weissig, MD is registered under Pulmonary Disease in Fullerton, California. Graduated from Duke University School of Medicine in 1980, 46 years ago. Practices with Providence Medical Foundation, a 1,465-clinician group, accepts Medicare assignment and offers telehealth. Licensed in California.

Years since qualifying
46
Trained at
Duke University School of Medicine
Licensed in
CA
In the registry since
2005
Specialties on file
2
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

2141 N Harbor Blvd Ste 25000
Fullerton, CA 92835-3827 Not confirmed with CMS for 13 years — call before visiting
Phone: (714) 626-8610
Fax: (714) 626-8655
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Pulmonary Disease Physician (primary) Taxonomy 207RP1001X · Licence G49175 (CA)
Internal Medicine Physician Taxonomy 207R00000X · Licence G49175 (CA)

Record details

NPI number1649266032
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedSeptember 21, 2005
Last updated in NPPESApril 25, 2013

Medicare enrollment

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

Medicare specialtyPULMONARY DISEASE
Medical schoolDUKE UNIVERSITY SCHOOL OF MEDICINE
Graduated 1980 (46 years in practice)
Group practice Providence Medical Foundation — 1465 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services
Practice locations5 on file with Medicare

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 patients529
Services billed 1,616 a service is one billed item, such as a visit, a test or a procedure
Average patient age77

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 $424 16 payments · 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.

  • Providence St. Joseph Hospital Hospital · Orange, CA
  • Providence St. Jude Medical Center Hospital · Fullerton, CA

Colleagues at Providence Medical Foundation

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 1465 clinicians in the practice; 12 are shown here.

Other providers in Fullerton