TOM ELLIS WILLIAMS MD
NPI 1932393220
Family Medicine in San Ysidro, CA
About Tom Ellis Williams Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
TOM ELLIS WILLIAMS MD (NPI 1932393220) is an individual family medicine provider in San Ysidro, California, licensed in California (A100446) and active in the NPI registry since August 2007. He is enrolled in Medicare PECOS and is a graduate of Other (2003).
NPPES Registry Identity
Specialties & Licenses
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Tom Ellis Williams Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignment
Medicare enrollment records show Tom Williams reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
San Diego, CA 92108
- Reassigned Medicare billing, California enrollment
- 13,921 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 92173 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
SAN YSIDRO, CA 92173
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Tom Williams's NPI number?
The NPI number for Tom Williams is 1932393220. It was assigned to this individual provider in the NPPES registry on August 30, 2007.
Where is Tom Williams located?
Tom Williams practices at 4004 Beyer Blvd, San Ysidro, CA 92173. The listed phone number is (619) 428-1330.
What is Tom Williams's specialty?
The primary specialty registered for this NPI is Family Medicine with taxonomy code 207Q00000X.
Is Tom Williams enrolled in Medicare?
Yes. Tom Williams is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organization bills Medicare for Tom Williams's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Tom Williams reassigns Medicare benefits to Southern California Permanente Medical Group (San Diego, CA). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Tom Williams's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
When was this NPI record last updated?
The NPPES record for Tom Williams was last updated on December 1, 2021. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Tom Ellis Williams, MD · NPI 1932393220
Family Medicine physician in San Ysidro, California. Individual provider, active in the CMS NPPES registry since August 30, 2007.
## Identity
- **NPI:** 1932393220 (Entity type: Individual)
- **Enumerated:** August 30, 2007
- **Primary specialty:** Family Medicine · taxonomy 207Q00000X
- **State license:** A100446 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 4004 BEYER BLVD, San Ysidro, CA 92173-2007
- **Phone:** (619) 428-1330 · **Fax:** (619) 428-7952
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** Southern California Permanente Medical Group (NPI 1023425972, San Diego, CA), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2003
## Record status
- **NPPES last updated:** December 1, 2021
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Source: [NPI Profile](https://npiprofile.com/npi/1932393220) · Data from the CMS NPPES public registry.