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

Dr. Gemma Guillermo, MD

Individual provider Psychiatry Physician · NPI 1831154418

Dr. Gemma Guillermo, MD practises Psychiatry in Redwood City, California. Graduated from Js Weill Medical College, Cornell University in 1995, 31 years ago. Practices with County of Santa Clara, a 993-clinician group and accepts Medicare assignment. Licensed in California.

Years since qualifying
31
Trained at
Js Weill Medical College, Cornell University
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

170 Alameda De Las Pulgas 1EAST Sequoia Hospital
Redwood City, CA 94062-2799
Phone: (650) 367-5559
Fax: (650) 368-3754
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Psychiatry Physician (primary) Taxonomy 2084P0800X · Licence 61066 (CA)

Record details

NPI number1831154418
Entity typeIndividual (Type 1)
GenderFemale
Credentials MD
Sole proprietorYes
NPI enumeratedApril 18, 2006
Last updated in NPPESFebruary 13, 2019

Medicare enrollment

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

Medicare specialtyPSYCHIATRY
Medical schoolJS WEILL MEDICAL COLLEGE, CORNELL UNIVERSITY
Graduated 1995 (31 years in practice)
Group practice County Of Santa Clara — 993 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 patients38
Services billed 223 a service is one billed item, such as a visit, a test or a procedure
Average patient age49

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 $139 1 payment · 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.

Colleagues at County of Santa Clara

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 993 clinicians in the practice; 12 are shown here.

Other providers in Redwood City