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

Dr. Oscar L. Chien, MD

Individual provider Geriatric Medicine (Internal Medicine) Physician · NPI 1679675904

Dr. Oscar L. Chien, MD practises Internal Medicine in San Gabriel, California. Qualified in 1990, 36 years ago. Practices as a sole proprietor and accepts Medicare assignment. Licensed in California.

Years since qualifying
36
Licensed in
CA
In the registry since
2006
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

1448 S San Gabriel Bl
San Gabriel, CA 91776
Phone: (626) 569-2888
Fax: (626) 569-9929
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Geriatric Medicine (Internal Medicine) Physician (primary) Taxonomy 207RG0300X · Licence A54999 (CA)

Record details

NPI number1679675904
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorYes
NPI enumeratedSeptember 5, 2006
Last updated in NPPESApril 2, 2020
Certification dateApril 2, 2020

Medicare enrollment

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

Medicare specialtyINTERNAL MEDICINE
Also practisesGERIATRIC MEDICINE
Medical schoolOTHER
Graduated 1990 (36 years in practice)
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 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 patients681
Services billed 5,279 a service is one billed item, such as a visit, a test or a procedure
Average patient age79

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.

Compensation for services other than consulting , including serving as faculty or as a speaker at a venue other than a continuing education program $6,730 5 payments
Food and Beverage $4,315 115 payments · a meal or drink at a meeting or visit, not a fee
Travel and Lodging $1,545 3 payments · travel or lodging paid or reimbursed, such as to attend a conference
Consulting Fee $1,250 1 payment
Education $33 2 payments · educational material or training, 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.

Other providers in San Gabriel