Sean Dennis Oconnor, M.D.
Internal Medicine Physician · Chicago, IL
Sean Dennis Oconnor, M.D. is an internal medicine physician with a practice address in Chicago, Illinois, and NPI 1609831528, issued on Apr 20, 2006. Check the license (Illinois 03697642, as entered in NPPES) on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.
- Name
- Sean Dennis Oconnor
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 03697642 IL
Self-reported in NPPES; status is on the state search - Practice location
- 211 E Chicago Ave Ste 1700, Chicago, IL 60611
- Phone
- (312) 944-6677
- Enumerated
- Apr 20, 2006
- Record last updated
- Mar 27, 2026
- Fax
- (312) 944-3346
- Medicare enrollment
- Enrolled (PECOS I20101028001354); may accept Medicare assignment
- Medical or professional school
- University Of Illinois College Of Med (Chi/Peor/Rock/Chm-Urb), 1994
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 7,238 in Illinois → Look up another NPI →
Also registered at 211 E Chicago Ave Ste 1700
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Sean Dennis Oconnor 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 03697642Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
47% more Medicare Part D claims than the average internal medicine physician in 2024
4,668 Medicare Part D claims for 312 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 14% of claims. 63 claims were for opioids.
Most prescribed
- Atorvastatin Calcium292 claims
- Rosuvastatin Calcium201 claims
- Amlodipine Besylate184 claims
- Levothyroxine Sodium179 claims
- Metoprolol Succinate166 claims
- Lisinopril129 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: $24.42
1 payment: food and beverage; the largest payer was Pfizer Inc. 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
- Rci (wrs) LLCPortage, IN
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Sean Dennis Oconnor among 7,238 internal medicine physician records in Illinois
Sean Dennis Oconnor, M.D. 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
- Graduated1994 · median 2003 among the 3,580 with a school on file
- Record last updated2026 · 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).
2,867 internal medicine physician records list a practice address in Chicago
They are 2,867 of the 63,379 NPPES records with a practice address in Chicago, and 7,238 internal medicine physician records in Illinois.
All 7,238 in Illinois → Every provider in Chicago → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
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- Arnold Grauer, MDChicago, IL 606111619960184
- James Hall, MDChicago, IL 606111649263153
- Frances Langdon, MDChicago, IL 606111063405546
- Michael Lee, MDChicago, IL 606111942293451
- Hazel Manzano, MDChicago, IL 606111801889316
- Chadwick Milstead, MDChicago, IL 606111740273259
Common questions
What is Sean Dennis Oconnor, M.D.'s NPI number?
Sean Dennis Oconnor, M.D.'s National Provider Identifier (NPI) is 1609831528, issued on Apr 20, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Sean Dennis Oconnor, M.D. located?
The NPPES record lists a practice address at 211 E Chicago Ave Ste 1700, Chicago, IL, 60611. Phone: (312) 944-6677. Providers update this record themselves, so call before visiting.
How can I verify Sean Dennis Oconnor, M.D.'s license?
NPPES lists Illinois license number 03697642, 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 Sean Dennis Oconnor, M.D. prescribe under Medicare Part D?
In 2024, Sean Dennis Oconnor, M.D. had 4,668 Medicare Part D claims for 312 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.