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

Individual provider Internal Medicine Physician · NPI 1528180361

Dr. William Lai, MD is an Internal Medicine in Fontana, California. Graduated from Ohio State University College of Medicine in 2004, 22 years ago. Practices with Southern California Permanente Medical Group, an 11,242-clinician group and accepts Medicare assignment. Licensed in California.

Years since qualifying
22
Trained at
Ohio State University College of Medicine
Licensed in
CA
In the registry since
2007
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

9961 Sierra Ave
Fontana, CA 92335-6720
Phone: (909) 427-5000
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Internal Medicine Physician (primary) Taxonomy 207R00000X · Licence A93123 (CA)

Record details

NPI number1528180361
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorYes
NPI enumeratedApril 4, 2007
Last updated in NPPESNovember 17, 2021
Certification dateNovember 17, 2021
Mailing address9961 Sierra Ave, Fontana, CA 92335-6720

Medicare enrollment

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

Medicare specialtyINTERNAL MEDICINE
Also practisesHOSPITALIST
Medical schoolOHIO STATE UNIVERSITY COLLEGE OF MEDICINE
Graduated 2004 (22 years in practice)
Group practice Southern California Permanente Medical Group — 11242 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

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