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

Dr. Michael Sean Duffy Sr., DO

Individual provider Internal Medicine Physician · NPI 1851399802

Dr. Michael Sean Duffy Sr., DO is an Internal Medicine Physician in San Diego, California. Practices as a sole proprietor. Licensed in California.

Licensed in
CA
In the registry since
2005
What do these letters mean?
DO — Doctor of Osteopathic Medicine
A fully licensed physician, trained like an MD with additional musculoskeletal training. Equivalent practice rights in all 50 states.

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Practice location Address checks out

1501 5th Ave Ste 100
San Diego, CA 92101-3251
Phone: (619) 647-5072
Fax: (619) 330-4782
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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 20A9616 (CA)

Record details

NPI number1851399802
Entity typeIndividual (Type 1)
GenderMale
Credentials DO
Sole proprietorYes
NPI enumeratedJuly 13, 2005
Last updated in NPPESSeptember 22, 2022
Certification dateSeptember 22, 2022

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