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

Dr. Mark S O'Brien, MD

Individual provider Family Medicine Physician · NPI 1124129267

Dr. Mark S O'Brien, MD is a Family Practice in Carmel, Indiana. Graduated from Indiana University School of Medicine in 1988, 38 years ago. Practices with Iu Health Medical Group, LLC, a 4,351-clinician group, works from 2 locations and accepts Medicare assignment. Licensed in Indiana.

Years since qualifying
38
Trained at
Indiana University School of Medicine
Licensed in
IN
In the registry since
2006
Specialties on file
2
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

11725 N Illinois St Ste 250
Carmel, IN 46032-3015
Phone: (317) 688-5300
Fax: (317) 688-5313
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 409 E Washington St, Butler, IN 46721-1175 — (260) 868-5843

Specialties & licences

Family Medicine Physician (primary) Taxonomy 207Q00000X · Licence 01037757A (IN)
Preventive Medicine/Occupational Environmental Medicine Physician Taxonomy 2083P0500X · Licence 01037757A (IN)

Record details

NPI number1124129267
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedSeptember 25, 2006
Last updated in NPPESJanuary 6, 2021
Certification dateJanuary 6, 2021
Mailing address250 N Shadeland Ave, Indianapolis, IN 46219-4959

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyFAMILY PRACTICE
Also practisesPREVENTIVE MEDICINE
Medical schoolINDIANA UNIVERSITY SCHOOL OF MEDICINE
Graduated 1988 (38 years in practice)
Group practice Iu Health Medical Group, Llc — 4351 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

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