Type 2 · Organization ✓ Active NPI ✓ Valid NPI checksum

Gary Birnbaum MD Prof Corp

Family Medicine Physician in Mill Valley, CA · enumerated 2018 · authorized official David Harnden, Administrative Manager.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1255807152

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Registry record

Entity type Organization (Type 2)

Legal business name Gary Birnbaum MD Prof Corp

Practice address 97 Vista Del Sol, Mill Valley, CA, 94941

Phone (415) 350-0639

Fax (415) 366-2882

Enumeration date Oct 17, 2018

Last updated in NPPES Oct 17, 2018

Taxonomy & classification

207Q00000X Family Medicine Physician Allopathic & Osteopathic Physicians Primary

Authorized official

Name David Harnden

Title Administrative Manager

Phone (415) 648-2021

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes — even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

Where is Gary Birnbaum MD Prof Corp located?

The practice location on file with NPPES is in Mill Valley, CA.

How current is this record?

Data comes from the CMS NPPES public dissemination file; this record was last updated in NPPES on 2018-10-17. Verify at npiregistry.cms.hhs.gov.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2018-10-17.