Gregory James Zahner, MD

Primary specialty

Internal Medicine PhysicianTaxonomy code 207R00000X

License

A201693 Issued in CA

Practice address

505 Parnassus Ave
San Francisco, CA 94143-2204

Phone

(415) 476-1000

NPI assigned

Mar 26, 2020

Last updated

Aug 8, 2025By the provider in NPPES

Sex

Male

Sole proprietor

No

Registry information is reported by the provider to CMS and is not verified. About this source

Specialties & licenses 2

Addresses

Medicare fee-for-service enrollment

Enrolled in MA, CA2 enrollments

Eligible to order & refer

• Part B services: Yes
• Medical equipment: Yes
• Home health: Yes
• Power mobility devices: Yes
• Hospice: Yes

Green means eligible to order or refer.

Enrollment records 2

Specialty

Internal Medicine

Education

University of California, San Francisco School of Medicine, 2020

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Group practices

Regents of the University of CaliforniaGroup PAC ID 4284547274, 706 clinicians

Practice addresses (Care Compare)

Hospital & facility affiliations

• UCSF Medical Center Hospital, San Francisco, CA, CCN 050454

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

State licenses

Practice roles

Locations

Interoperability endpoints

• Direct secure messaging: gzahner62438@direct-ucsfmedicalcenter.org

Organizations this provider is connected to: Medicare benefit reassignments (the organization bills Medicare for this provider’s services), Care Compare group memberships, National Provider Directory roles and organizations whose NPPES authorized official is this provider.

• Regents of the University of California

  dba UCSF Dept of Medicine General Medicine

  • Internal Medicine Physician
  • San Francisco, CA
  • NPI 1760552343
  Medicare reassignment Care Compare group NPD
• UCSF Medical Group Business Services

  • Internal Medicine Physician
  • San Francisco, CA
  • NPI 1477624104
  Medicare reassignment NPD
• University of California San Francisco

  dba UCSF Pediatrics Group

  • Pediatrics Physician
  • San Francisco, CA
  • NPI 1861578973
  Medicare reassignment NPD
• Massachusetts General Physicians Organization Inc

  • Dermatology Physician
  • Boston, MA
  • NPI 1801874573

  Internal Medicine

  Medicare reassignment NPD
• The General Hospital Corporation

  • General Acute Care Hospital
  • Boston, MA
  • NPI 1023049236
  Medicare reassignment NPD
• UCSF Medical Group Business Services

  dba UCSF Orthotic and Prosthetic Center - Gateway Medical Building

  • Health Service Clinic/Center
  • San Francisco, CA
  • NPI 1194115246
  NPD
• University of California San Francisco

  dba UCSF Surgical Group

  • Surgery Physician
  • San Francisco, CA
  • NPI 1346329380
  NPD
• University of California San Francisco

  dba UCSF Outpatient Pharmacy at Parnassus

  • Community/Retail Pharmacy
  • San Francisco, CA
  • NPI 1659141711
  NPD
• Regents of the University of California

  dba UCSF Department of Medicine Rheumatology

  • Rheumatology Physician
  • San Francisco, CA
  • NPI 1881763597
  NPD (past)
• University of California San Francisco Medical Center

  dba UCSF Medical Center

  • General Acute Care Hospital
  • San Francisco, CA
  • NPI 1144325440
  NPD (past)

Hospitals and other facilities this clinician is affiliated with according to Medicare Care Compare.

• University of California, San Francisco

  dba UCSF Medical Center

  • General Acute Care Hospital
  • San Francisco, CA
  • NPI 1689772592
  Care Compare affiliation

The complete NPPES record for this NPI in the NPI Registry API format.

{
    "created_epoch": "1585180800000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1754611200000",
    "number": "1427685767",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "505 PARNASSUS AVE",
            "city": "SAN FRANCISCO",
            "state": "CA",
            "postal_code": "941432204",
            "telephone_number": "415-476-1000"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "505 PARNASSUS AVE",
            "city": "SAN FRANCISCO",
            "state": "CA",
            "postal_code": "941432204",
            "telephone_number": "415-476-1000"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "ZAHNER",
        "first_name": "GREGORY",
        "middle_name": "JAMES",
        "name_prefix": "Dr.",
        "credential": "MD",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2020-03-26",
        "last_updated": "2025-08-08",
        "certification_date": "2025-08-08",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207R00000X",
            "taxonomy_group": "",
            "desc": "Internal Medicine",
            "state": "MA",
            "license": "1013382",
            "primary": false
        },
        {
            "code": "207R00000X",
            "taxonomy_group": "",
            "desc": "Internal Medicine",
            "state": "CA",
            "license": "A201693",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

• Ali Zahir
• Heather Uson Zahiri, RN, NP
• Mehrnaz Zahiri, PHARM.D.
• Gayle Sue Zahler, LCSW
• Marlena Elizabeth Zahm, MFTI
• Ali Akbar Zaidi, MD
• Juana Agnes Zaidi
• Bijan Arian Zaimi
• Rochelle Zak, M.D.
• Hesham Mostafa Zakaria, MD

• Internal Medicine Physician in San Francisco, CA
• Providers in San Francisco, CA by specialty
• Internal Medicine Physician in California

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Aug 8, 2025; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments; Order and Referring.
• Medicare Care Compare (CMS): clinician profile, group practices, facility affiliations, MIPS scores and star ratings.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.