Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
NPIDirectory

Justin Mager, MD

Individual provider Internal Medicine Physician · NPI 1669672739

Justin Mager, MD is an Internal Medicine Physician in Mill Valley, California. Licensed in California. Registered with an NPI since 2007.

Licensed in
CA
In the registry since
2007
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

239 Miller Ave #8
Mill Valley, CA 94941-2841
Phone: (415) 730-4235
Fax: (415) 952-9345
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Internal Medicine Physician (primary) Taxonomy 207R00000X · Licence A95972 (CA)

Record details

NPI number1669672739
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJuly 18, 2007
Last updated in NPPESNovember 5, 2012
Mailing address239 Miller Ave, 8, Mill Valley, CA 94941-2841

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