ANDREW SYDNEY WILLIAMS M.D.
NPI 1528075389
Ophthalmology in San Mateo, CA
About Andrew Sydney Williams M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
ANDREW SYDNEY WILLIAMS M.D. (NPI 1528075389) is an individual ophthalmology provider in San Mateo, California, licensed in California (G56863) and active in the NPI registry since August 2006. He is enrolled in Medicare PECOS.
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 (PECOS)
Andrew Sydney Williams M.d. is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Medicare Billing Reassignments
4Medicare enrollment records show Andrew Williams reassigns Medicare billing to 4 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
San Mateo, CA 94401
- Reassigned Medicare billing, California enrollment
- 3 clinicians in this Medicare group
San Francisco, CA 94110
- Reassigned Medicare billing, California enrollment
- 842 clinicians in this Medicare group
San Francisco, CA 94143
- Reassigned Medicare billing, California enrollment
- 5,645 clinicians in this Medicare group
San Francisco, CA 94122
- Reassigned Medicare billing, California enrollment
- 5,544 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 94401 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 MATEO, CA 94401
SAN MATEO, CA 94401
SAN MATEO, CA 94401
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 Andrew Williams's NPI number?
The NPI number for Andrew Williams is 1528075389. It was assigned to this individual provider in the NPPES registry on August 2, 2006.
Where is Andrew Williams located?
Andrew Williams practices at 101 S San Mateo Dr Ste 306, San Mateo, CA 94401. The listed phone number is (650) 696-7070.
What is Andrew Williams's specialty?
The primary specialty registered for this NPI is Ophthalmology with taxonomy code 207W00000X.
Is Andrew Williams enrolled in Medicare?
Yes. Andrew Williams is registered in the Medicare PECOS enrollment system.
Which organizations bill Medicare for Andrew Williams's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Andrew Williams reassigns Medicare benefits to 4 organizations: A Sydney Williams And Associates Inc (San Mateo, CA), University Of California Sfgh Medical Group (San Francisco, CA), University Of California San Francisco (San Francisco, CA) and Ucsf Medical Group Business Services (San Francisco, CA). Each 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 Andrew 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 Andrew Williams was last updated on March 7, 2019. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 7 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.
# Andrew Sydney Williams, M.D. · NPI 1528075389
Ophthalmology physician in San Mateo, California. Individual provider, active in the CMS NPPES registry since August 2, 2006.
## Identity
- **NPI:** 1528075389 (Entity type: Individual)
- **Enumerated:** August 2, 2006
- **Primary specialty:** Ophthalmology · taxonomy 207W00000X
- **State license:** G56863 (California)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 101 S SAN MATEO DR, STE 306, San Mateo, CA 94401-3844
- **Phone:** (650) 696-7070 · **Fax:** (650) 348-1314
## Medicare
- **Medicare:** Enrolled in Medicare (PECOS)
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 4 organizations under Medicare reassignment (form CMS-855R): A Sydney Williams And Associates Inc (NPI 1073096160, San Mateo, CA); University Of California Sfgh Medical Group (NPI 1174598296, San Francisco, CA); University Of California San Francisco (NPI 1346329380, San Francisco, CA); Ucsf Medical Group Business Services (NPI 1477624104, San Francisco, CA) · CMS Revalidation Reassignment List, October 2026 release
## Record status
- **NPPES last updated:** March 7, 2019
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Source: [NPI Profile](https://npiprofile.com/npi/1528075389) · Data from the CMS NPPES public registry.