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

Mark Day, DO

Individual provider Family Medicine Physician · NPI 1164436994

Mark Day, DO is registered under Family Practice in Las Vegas, Nevada. Graduated from Des Moines University of Osteopathic Medicine and Health Sciences in 1990, 36 years ago. Practices with Optum Medical Group II Rhodes P C, a 302-clinician group, works from 2 locations and accepts Medicare assignment. Licensed in Nevada.

Years since qualifying
36
Trained at
Des Moines University of Osteopathic Medicine and Health Sciences
Licensed in
NV
In the registry since
2006
What do these letters mean?
DO — Doctor of Osteopathic Medicine
A fully licensed physician, trained like an MD with additional musculoskeletal training. Equivalent practice rights in all 50 states.

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Practice location Address checks out

1655 E Cactus Ave Ste 400
Las Vegas, NV 89183-7723
Phone: (702) 724-8777
Fax: (702) 724-8749
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 56 N Pecos Rd, Henderson, NV 89074-0698 — (702) 456-9100

Specialties & licences

Family Medicine Physician (primary) Taxonomy 207Q00000X · Licence 656 (NV)

Record details

NPI number1164436994
Entity typeIndividual (Type 1)
GenderMale
Credentials DO
Sole proprietorNo
NPI enumeratedJuly 28, 2006
Last updated in NPPESNovember 6, 2025
Certification dateNovember 6, 2025

Medicare enrollment

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

Medicare specialtyFAMILY PRACTICE
Medical schoolDES MOINES UNIVERSITY OF OSTEOPATHIC MEDICINE AND HEALTH SCIENCES
Graduated 1990 (36 years in practice)
Group practice Optum Medical Group Ii Rhodes P C — 302 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
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 patients364
Services billed 770 a service is one billed item, such as a visit, a test or a procedure
Average patient age76

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 $294 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.

Colleagues at Optum Medical Group II Rhodes P C

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 302 clinicians in the practice; 12 are shown here.

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