DR. GREGORY JAMES ZAHNER MD
NPI 1427685767
Internal Medicine in San Francisco, CA
About Dr. Gregory James Zahner Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. GREGORY JAMES ZAHNER MD (NPI 1427685767) is an individual internal medicine provider in San Francisco, California, licensed in California (A201693) and active in the NPI registry since March 2020. He is enrolled in Medicare PECOS and is a graduate of University Of California, San Francisco School Of Medicine (2020).
NPPES Registry Identity
Specialties & Licenses
Accepted Insurance
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
Dr. Gregory James Zahner 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 Reassignments
5Medicare enrollment records show Gregory Zahner reassigns Medicare billing to 5 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
San Francisco, CA 94143
- Reassigned Medicare billing, California enrollment
- 2,112 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
Boston, MA 02114
- Reassigned Medicare billing, Massachusetts enrollment
- 6,360 clinicians in this Medicare group
Boston, MA 02114
- Reassigned Medicare billing, Massachusetts enrollment
- 6,234 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 94143 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 FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
SAN FRANCISCO, CA 94143
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 Gregory Zahner's NPI number?
The NPI number for Gregory Zahner is 1427685767. It was assigned to this individual provider in the NPPES registry on March 26, 2020.
Where is Gregory Zahner located?
Gregory Zahner practices at 505 Parnassus Ave, San Francisco, CA 94143. The listed phone number is (415) 476-1000.
What is Gregory Zahner's specialty?
The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.
Is Gregory Zahner enrolled in Medicare?
Yes. Gregory Zahner 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 organizations bill Medicare for Gregory Zahner's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Gregory Zahner reassigns Medicare benefits to 5 organizations: Regents Of The University Of California (San Francisco, CA), University Of California San Francisco (San Francisco, CA), Ucsf Medical Group Business Services (San Francisco, CA), Massachusetts General Physicians Organization Inc (Boston, MA) and The General Hospital Corporation (Boston, MA). 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 Gregory Zahner's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Gregory Zahner accept?
Health plans from Taro Health list Gregory Zahner as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
When was this NPI record last updated?
The NPPES record for Gregory Zahner was last updated on August 8, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 14 months 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.
# Dr. Gregory James Zahner, MD · NPI 1427685767
Internal Medicine physician in San Francisco, California. Individual provider, active in the CMS NPPES registry since March 26, 2020.
## Identity
- **NPI:** 1427685767 (Entity type: Individual)
- **Enumerated:** March 26, 2020
- **Primary specialty:** Internal Medicine · taxonomy 207R00000X
- **State license:** A201693 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 505 PARNASSUS AVE, San Francisco, CA 94143-2204
- **Phone:** (415) 476-1000
## 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:** 5 organizations under Medicare reassignment (form CMS-855R): Regents Of The University Of California (NPI 1376613943, San Francisco, CA); University Of California San Francisco (NPI 1346329380, San Francisco, CA); Ucsf Medical Group Business Services (NPI 1477624104, San Francisco, CA); Massachusetts General Physicians Organization Inc (NPI 1801874573, Boston, MA); The General Hospital Corporation (NPI 1023049236, Boston, MA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** University Of California, San Francisco School Of Medicine, class of 2020
## Record status
- **NPPES last updated:** August 8, 2025
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Source: [NPI Profile](https://npiprofile.com/npi/1427685767) · Data from the CMS NPPES public registry.