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

Dr. John M. O'Brien, MD

Individual provider Internal Medicine Physician · NPI 1376572891

Dr. John M. O'Brien, MD is an Internal Medicine Physician in Chicago, Illinois. Licensed in Illinois. Registered with an NPI since 2006.

Licensed in
IL
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

1901 W Harrison St
Chicago, IL 60612-3714
Phone: (312) 864-6000
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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 036082069 (IL)

Record details

NPI number1376572891
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJune 30, 2006
Last updated in NPPESApril 28, 2021
Certification dateApril 28, 2021

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