Robert Jen, M.D.
Internal Medicine Physician · Oak Lawn, IL
Robert Jen, M.D. is an internal medicine physician with a practice address in Oak Lawn, Illinois, and NPI 1104169994, issued on Apr 1, 2013. Check the license (Illinois 125.063485, as entered in NPPES) on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.
- Name
- Robert Jen
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 125.063485 IL
Self-reported in NPPES; status is on the state search - Practice location
- 4440 W 95TH St, Oak Lawn, IL 60453
- Phone
- (708) 684-8000
- Enumerated
- Apr 1, 2013
- Record last updated
- Oct 6, 2025
- Medicare enrollment
- Enrolled (PECOS I20161227000964); accepts Medicare assignment
- Medical or professional school
- University Of Cincinnati College Of Medicine, 2013
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 7,238 in Illinois → Look up another NPI →
Also registered at 4440 W 95TH St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Katherine Absalon, MOT, OTR/LOccupational Therapist1457753436
- Tassneem Abu-Rezeq, DNP, APRN, CPNP-ACPediatric Nurse Practitioner1831904663
Verify Robert Jen 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 125.063485Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
96% fewer Medicare Part D claims than the average internal medicine physician in 2024
133 Medicare Part D claims for 68 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Most prescribed
- Pantoprazole Sodium15 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.
Bills Medicare through one group practice
- Advocate Health And Hospitals CorporationBuffalo Grove, IL
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Robert Jen among 7,238 internal medicine physician records in Illinois
Robert Jen, 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 2013, is newer than 57% of them.
- NPI issued2013 · 57% of these records are older, 41% newer
- In a Medicare fileYes · 73% of these records are
- In the CMS Doctors and Clinicians fileYes · 50% of these records are
- Graduated2013 · median 2003 among the 3,580 with a school on file
- Record last updated2025 · 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).
173 internal medicine physician records list a practice address in Oak Lawn
They are 173 of the 2,993 NPPES records with a practice address in Oak Lawn, and 7,238 internal medicine physician records in Illinois.
All 7,238 in Illinois → Every provider in Oak Lawn → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Robert Chalupczak, M.D.Oak Lawn, IL 604531679505051
- Anupam Goel, MDOak Lawn, IL 604531013957570
- Joseph Kowalczyk, MDOak Lawn, IL 604531831166255
- Vinay Kumar, MDOak Lawn, IL 604531639138217
- Eugene Muzykansky, MDOak Lawn, IL 604531457328874
- Win Myint, MDOak Lawn, IL 604531063412062
- Robert Raines, MDOak Lawn, IL 604531164499596
- Mark Reiter, M.D.Oak Lawn, IL 604531902864408
Common questions
What is Robert Jen, M.D.'s NPI number?
Robert Jen, M.D.'s National Provider Identifier (NPI) is 1104169994, issued on Apr 1, 2013. An NPI identifies a provider in billing; it is not a license.
Where is Robert Jen, M.D. located?
The NPPES record lists a practice address at 4440 W 95TH St, Oak Lawn, IL, 60453. Phone: (708) 684-8000. Providers update this record themselves, so call before visiting.
How can I verify Robert Jen, M.D.'s license?
NPPES lists Illinois license number 125.063485, 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 Robert Jen, M.D. prescribe under Medicare Part D?
In 2024, Robert Jen, M.D. had 133 Medicare Part D claims for 68 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.