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

Dr. Charles Hsiao-Kung Feng, MD

Individual provider Allergy & Immunology Physician · NPI 1518260306

Dr. Charles Hsiao-Kung Feng, MD practises Allergy/Immunology in Mountain View, California. Qualified in 2009, 17 years ago. Practices with Sutter Bay Medical Foundation, a 3,762-clinician group, accepts Medicare assignment and offers telehealth. Licensed in California.

Years since qualifying
17
Licensed in
CA
In the registry since
2010
Specialties on file
2
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

See every abbreviation used in this directory →

Practice location Address checks out

701 E El Camino Real
Mountain View, CA 94040-2833 Not confirmed with CMS for 11 years — call before visiting
Phone: (650) 934-7888
Show map & directions

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

Specialties & licences

Allergy & Immunology Physician (primary) Taxonomy 207K00000X · Licence A115080 (CA)
Internal Medicine Physician Taxonomy 207R00000X · Licence A115080 (CA)

Record details

NPI number1518260306
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedDecember 16, 2010
Last updated in NPPESSeptember 23, 2015

Medicare enrollment

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

Medicare specialtyALLERGY/IMMUNOLOGY
Medical schoolOTHER
Graduated 2009 (17 years in practice)
Group practice Sutter Bay Medical Foundation — 3762 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services
Practice locations3 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 patients114
Services billed 4,449 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.

Colleagues at Sutter Bay Medical Foundation

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 3762 clinicians in the practice; 12 are shown here.

Other providers in Mountain View