Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

Brian O'Leary, MD

Individual provider Internal Medicine Physician · NPI 1295702439

Brian O'Leary, MD practises Internal Medicine in Naperville, Illinois. Graduated from Northwestern University Feinberg Medical School in 1985, 41 years ago. Practices with Dupage Medical Group Ltd, a 1,328-clinician group, accepts Medicare assignment and offers telehealth. Licensed in Illinois.

Years since qualifying
41
Trained at
Northwestern University Feinberg Medical School
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

1964 Springbrook Square Dr Ste 104
Naperville, IL 60564-5949
Phone: (630) 946-2565
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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 036073069 (IL)

Record details

NPI number1295702439
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedMarch 7, 2006
Last updated in NPPESSeptember 24, 2021
Certification dateSeptember 24, 2021

Medicare enrollment

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

Medicare specialtyINTERNAL MEDICINE
Medical schoolNORTHWESTERN UNIVERSITY FEINBERG MEDICAL SCHOOL
Graduated 1985 (41 years in practice)
Group practice Dupage Medical Group Ltd — 1328 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients136
Services billed 1,325 a service is one billed item, such as a visit, a test or a procedure
Average patient age75

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $322 16 payments · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician. Those with a page here are linked.

  • Edward Hospital Hospital · Naperville, IL
  • Dmj Home Health Services, Inc Home health agency · Aurora, IL
  • Residential Home Health Home health agency · Lisle, IL · listed as Residential Home Health Illinois, LLC
  • Northwestern Medicine Central Dupage Hospital Hospital · Winfield, IL
  • Lightways Hospice And Serious Illness Care Hospice · Joliet, IL

Colleagues at Dupage Medical Group Ltd

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 1328 clinicians in the practice; 12 are shown here.

Other providers in Naperville