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

Dr. Mark Allen Rosen, MD

Individual provider Critical Care Medicine (Internal Medicine) Physician · NPI 1427108851

Dr. Mark Allen Rosen, MD practises Internal Medicine in Orange, California. Graduated from Loyola University of Chicago, Stritch School of Medicine in 1979, 47 years ago. Practices with Uc Regents, a 306-clinician group and accepts Medicare assignment. Licensed in California.

Years since qualifying
47
Trained at
Loyola University of Chicago, Stritch School of Medicine
Licensed in
CA
In the registry since
2007
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

101 The City Dr S Bldg 53 Rm 119 RT 81
Orange, CA 92868-3201 Not confirmed with CMS for 19 years — call before visiting
Phone: (714) 456-5150
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Critical Care Medicine (Internal Medicine) Physician (primary) Taxonomy 207RC0200X · Licence G43522 (CA)

Record details

NPI number1427108851
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorYes
NPI enumeratedJanuary 10, 2007
Last updated in NPPESJuly 8, 2007

Medicare enrollment

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

Medicare specialtyINTERNAL MEDICINE
Also practisesPULMONARY DISEASE
Medical schoolLOYOLA UNIVERSITY OF CHICAGO, STRITCH SCHOOL OF MEDICINE
Graduated 1979 (47 years in practice)
Group practice Uc Regents — 306 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

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 patients57
Services billed 129 a service is one billed item, such as a visit, a test or a procedure
Average patient age72

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 $67 3 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.

  • Uci Health-Orange Hospital · Orange, CA

Colleagues at Uc Regents

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 306 clinicians in the practice; 12 are shown here.

Other providers in Orange