Esther Won, MD
NPI 1902973803 · Geriatric Medicine (Family Medicine) Physician · Fontana, CA
Enrolled with Medicare as Practitioner - Hospice/Palliative Care · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Esther Won, MD is a Geriatric Medicine (Family Medicine) Physician provider in Fontana, CA (NPI 1902973803).
Provider details
- NPI number
- 1902973803
- Entity type
- Individual
- Primary specialty
- Geriatric Medicine (Family Medicine) PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- G58458 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
19 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 14 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 26 | 18 |
| Pregabalin | 24 | — |
| Tramadol Hcl | 21 | — |
| Simvastatin | 17 | — |
| Ondansetron Hcl | 14 | — |
| Amlodipine Besylate | 13 | — |
| Gabapentin | 13 | — |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-11-29
- Last updated
- 2021-11-29
Frequently asked questions
- What is Esther Won's NPI number?
- Esther Won's National Provider Identifier (NPI) is 1902973803, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Esther Won's specialty?
- Esther Won is listed in the NPPES registry with a primary specialty of Geriatric Medicine (Family Medicine) Physician (Allopathic & Osteopathic Physicians).
- Where is Esther Won located?
- Esther Won's practice location on file with NPPES is 9961 Sierra Ave, Fontana, CA 92335-6720.
- What is Esther Won's phone number?
- The practice phone number listed in the NPPES registry for Esther Won is (909) 427-3910.
- Does Esther Won accept Medicare?
- Esther Won is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Esther Won's NPI active?
- Yes — Esther Won's NPI (1902973803) is active in the NPPES registry as of the last update on 2021-11-29.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.