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

Dr. William Tsai, DO

Individual provider Family Medicine Physician · NPI 1285620443

Dr. William Tsai, DO is a Family Practice in Upland, California. Qualified in 1996, 30 years ago. Accepts Medicare assignment and offers telehealth. Licensed in California.

Years since qualifying
30
Licensed in
CA
In the registry since
2005
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

510 N 13th Ave Ste 101
Upland, CA 91786-4973
Phone: (909) 985-8838
Fax: (909) 985-8899
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Family Medicine Physician (primary) Taxonomy 207Q00000X · Licence 20A7115 (CA)

Record details

NPI number1285620443
Entity typeIndividual (Type 1)
GenderMale
Credentials DO
Sole proprietorNo
NPI enumeratedSeptember 23, 2005
Last updated in NPPESApril 24, 2024
Certification dateApril 24, 2024
Mailing address510 N 13th Ave Ste 101, Upland, CA 91786-4973

Medicare enrollment

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

Medicare specialtyFAMILY PRACTICE
Medical schoolOTHER
Graduated 1996 (30 years in practice)
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services
Practice locations2 on file with Medicare

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