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

Individual provider Internal Medicine Physician · NPI 1225042088

Walter C Prehn, MD is an Internal Medicine Physician in Sonoma, California. Practices as a sole proprietor. Licensed in California.

Licensed in
CA
In the registry since
2006
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

181 Andrieux St Ste 206
Sonoma, CA 95476-6920
Phone: (707) 495-7762
Fax: (707) 938-7337
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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 G254540 (CA)

Record details

NPI number1225042088
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorYes
NPI enumeratedJuly 28, 2006
Last updated in NPPESSeptember 25, 2012

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