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

Dr. Matthew Nienaber, DO

Individual provider Internal Medicine Physician · NPI 1033535182

Dr. Matthew Nienaber, DO practises Internal Medicine in Santa Monica, California. Qualified in 2014, 12 years ago. Practices with Providence Saint Johns Medical Foundation, a 285-clinician group, works from 2 locations, accepts Medicare assignment and offers telehealth. Licensed in California.

Years since qualifying
12
Licensed in
CA
In the registry since
2014
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

1821 Wilshire Blvd Ste 100
Santa Monica, CA 90403-5627
Phone: (310) 575-3100
Fax: (310) 575-3102
Show map & directions

Directions in Google Maps · Apple Maps · OpenStreetMap

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 355 Abbott St Ste 100, Salinas, CA 93901-4484 — (831) 751-7070

Specialties & licences

Internal Medicine Physician (primary) Taxonomy 207R00000X · Licence 20A14759 (CA)

Record details

NPI number1033535182
Entity typeIndividual (Type 1)
GenderMale
Credentials DO
Sole proprietorNo
NPI enumeratedMarch 13, 2014
Last updated in NPPESMay 28, 2026
Certification dateMay 28, 2026

Medicare enrollment

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

Medicare specialtyINTERNAL MEDICINE
Medical schoolOTHER
Graduated 2014 (12 years in practice)
Group practice Providence Saint Johns Medical Foundation — 285 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.

Removal of skin lesions 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 patients116
Services billed 653 a service is one billed item, such as a visit, a test or a procedure
Average patient age74

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 $857 38 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. Those with a page here are linked.

  • Saint John'S Health Center Hospital · Santa Monica, CA · listed as Providence Saint John's Health Center
  • Salinas Valley Health Medical Center Hospital · Salinas, CA
  • Providence Home Health La County South Home health agency · Torrance, CA

Colleagues at Providence Saint Johns Medical Foundation

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 285 clinicians in the practice; 12 are shown here.

Other providers in Santa Monica