NPPES file of Aug 9, 2026

Gillian Brennan

Neonatal-Perinatal Medicine Physician · Chicago, IL

Gillian Brennan is a neonatal-perinatal medicine physician with a practice address in Chicago, Illinois, and NPI 1174782437, issued on Jun 3, 2008. Check the license (Illinois 036122278, as entered in NPPES) on the Illinois Department of Financial and Professional Regulation; the federal record below is the public data PlainDoctor holds for this provider.

Record from CMS NPPES, file of Aug 9, 2026 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1174782437
Name
Gillian Brennan
Primary taxonomy
Neonatal-Perinatal Medicine Physician 2080N0001X
License number
036122278 IL
Self-reported in NPPES; status is on the state search
Practice location
5841 S Maryland Ave, Chicago, IL 60637
Phone
(888) 824-0200
Enumerated
Jun 3, 2008
Record last updated
Oct 24, 2022
Medicare enrollment
Enrolled (PECOS I20251013002859); may accept Medicare assignment
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). Enrollment, assignment, school and telehealth: CMS Doctors and Clinicians file, Aug 2026. A record is not a license: verify it with the state board.
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8 nearest neonatal-perinatal medicine physician records → All 362 in Illinois → Look up another NPI →

Also registered at 5841 S Maryland Ave

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Ma. Theresa Abaring, CRNACertified Registered Nurse Anesthetist1962647586
  2. Rouzbeh AbbasgholizadehRetina Specialist (Ophthalmology) Physician1881510030
  3. Jehad Abdalla, MDSleep Medicine (Internal Medicine) Physician1053898684
  4. Sara Abdelaziz, MDEndocrinology, Diabetes & Metabolism Physician1598258089
  5. Noor Abdelrahman, PA-CPhysician Assistant1851012413
  6. Unknown Abdul Hanan, MDBlood Banking & Transfusion Medicine Physician1750022240

Verify Gillian Brennan in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersIllinois Department of Financial and Professional Regulation
    Search for license 036122278    Check the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Open the Illinois license search

PlainDoctor does not match the HHS-OIG exclusion list to individual records: most entries carry no NPI. Search the OIG exclusion list by name.

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Gillian Brennan among 362 neonatal-perinatal medicine physician records in Illinois

Gillian Brennan is one of 362 neonatal-perinatal medicine physician records with a practice address in Illinois. 15% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does not. Its NPI, issued in 2008, is newer than 55% of them.

  • NPI issued2008 · 55% of these records are older, 39% newer
  • In a Medicare fileNo · 15% of these records are
  • In the CMS Doctors and Clinicians fileYes · 7% of these records are
  • Graduated2004 · median 2004 among the 25 with a school on file
  • Record last updated2022 · 51% of these records were not updated in five years or more

Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 2080N0001X and a Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).

Neonatal-Perinatal Medicine Physician providers in Illinois

There are 362 neonatal-perinatal medicine physician records in Illinois. No Medicare prescribing, quality score, industry payment or hospital affiliation is published for this NPI.

All 362 in Illinois → Every provider in Chicago → Neonatal-Perinatal Medicine Physician nationwide →

The 8 neonatal-perinatal medicine physician records with the nearest ZIP codes

  1. Ansul AsadChicago, IL 606371841449493
  2. Basharat Buchh, MDChicago, IL 606371609802107
  3. Christine CarlosChicago, IL 606371184986861
  4. Ama Fordwor-Koranteng, MDChicago, IL 606371013036151
  5. Oussama Itani, MDChicago, IL 606371083640361
  6. Kelly Kelly, M.D.Chicago, IL 606371780979302
  7. Jeremy MarksChicago, IL 606371962552901
  8. Tomas MunozChicago, IL 606371710225263

Common questions

What is Gillian Brennan's NPI number?

Gillian Brennan's National Provider Identifier (NPI) is 1174782437, issued on Jun 3, 2008. An NPI identifies a provider in billing; it is not a license.

Where is Gillian Brennan located?

The NPPES record lists a practice address at 5841 S Maryland Ave, Chicago, IL, 60637. Phone: (888) 824-0200. Providers update this record themselves, so call before visiting.

How can I verify Gillian Brennan's license?

NPPES lists Illinois license number 036122278, 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.

Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. An NPI identifies who bills; it is not a license.

Written with AI tools from the named public files; every figure is computed from those files (how it is made).

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.