Brian O'Leary, MD
Internal Medicine Physician · Naperville, IL
Brian O'Leary, MD is an internal medicine physician with a practice address in Naperville, Illinois, and NPI 1295702439, issued on Mar 7, 2006. Check the license (Illinois 036073069, as entered in NPPES) on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.
- Name
- Brian O'Leary
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 036073069 IL
Self-reported in NPPES; status is on the state search - Practice location
- 1964 Springbrook Square Dr, Naperville, IL 60564
- Phone
- (630) 946-2565
- Enumerated
- Mar 7, 2006
- Record last updated
- Sep 24, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicaid ID
- 036073069 IL
- Medicare enrollment
- Enrolled (PECOS I20040127001086); accepts Medicare assignment
- Medical or professional school
- Northwestern University Feinberg Medical School, 1985
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 7,238 in Illinois → Look up another NPI →
Also registered at 1964 Springbrook Square Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Patricia Duda - Tharani, NPAdult Health Nurse Practitioner1548655103
- Katherine Sikic, ANP-BCAdult Health Nurse Practitioner1124269592
- Blazej Woszczynski, PHARMDPharmacist1396166690
Verify Brian O'Leary in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersIllinois Department of Financial and Professional Regulation
Search for license 036073069Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
3.6 times the Medicare Part D claims of the average internal medicine physician in 2024
11,344 Medicare Part D claims for 591 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 11% of claims. 665 claims were for opioids.
Most prescribed
- Atorvastatin Calcium590 claims
- Levothyroxine Sodium388 claims
- Hydrocodone-Acetaminophen376 claims
- Rosuvastatin Calcium318 claims
- Losartan Potassium315 claims
- Amlodipine Besylate308 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Industry payments in 2024: $405.39
22 payments; by number, the most common kind was food and beverage; the largest payer was Lilly USA, LLC. The 50,334 providers of this specialty with any payment received $1,303.06 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Dupage Medical Group LtdNaperville, IL
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Brian O'Leary among 7,238 internal medicine physician records in Illinois
Brian O'Leary, MD is one of 7,238 internal medicine physician records with a practice address in Illinois. 73% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 7% of them.
- NPI issued2006 · 7% of these records are older, 61% newer
- In a Medicare fileYes · 73% of these records are
- In the CMS Doctors and Clinicians fileYes · 50% of these records are
- Graduated1985 · median 2003 among the 3,580 with a school on file
- Record last updated2021 · 47% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
75 internal medicine physician records list a practice address in Naperville
They are 75 of the 4,634 NPPES records with a practice address in Naperville, and 7,238 internal medicine physician records in Illinois.
All 7,238 in Illinois → Every provider in Naperville → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Iffat Ahmed, D.O.Naperville, IL 605641063668192
- Hardeep Arora, M.D.Naperville, IL 605641922057926
- Nazish Ekram, M.D.Naperville, IL 605641346496965
- Aristidis Hatzidimitriadis, MDNaperville, IL 605641508027855
- Matthew Strauch, D.O.Naperville, IL 605641477780328
- Douglas Tran, MDNaperville, IL 605641144270976
- Khalda Abbasi, MDNaperville, IL 605631487705240
- Yumna Ahmad, MDNaperville, IL 605631952938284
Common questions
What is Brian O'Leary, MD's NPI number?
Brian O'Leary, MD's National Provider Identifier (NPI) is 1295702439, issued on Mar 7, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Brian O'Leary, MD located?
The NPPES record lists a practice address at 1964 Springbrook Square Dr, Naperville, IL, 60564. Phone: (630) 946-2565. Providers update this record themselves, so call before visiting.
How can I verify Brian O'Leary, MD's license?
NPPES lists Illinois license number 036073069, as entered by the provider. Search the Illinois Department of Financial and Professional Regulation at https://idfpr.illinois.gov/checklicense.html. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Brian O'Leary, MD prescribe under Medicare Part D?
In 2024, Brian O'Leary, MD had 11,344 Medicare Part D claims for 591 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.