Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Thomas J Nielsen, M.D.

Otolaryngology Physician in Chicago, IL · enumerated 2005.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1235138546

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)

Name Dr. Thomas J Nielsen

Credential M.D.

Sex Male

Practice address 1611 W Harrison St, Suite 550, Chicago, IL, 60612

Phone (312) 942-6100

Fax (312) 942-6225

Enumeration date Jul 19, 2005

Last updated in NPPES May 4, 2011

Taxonomy & licenses

207Y00000X Otolaryngology Physician Allopathic & Osteopathic Physicians · License 036072375 (IL) Primary

207YX0007X Plastic Surgery within the Head & Neck (Otolaryngology) Physician Allopathic & Osteopathic Physicians · License 036-072375 (IL) Secondary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier	Type	State	Issuer
036072375	Medicaid	IL	-
CB1567	Other	IL	RRMC

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

What is the NPI number for Thomas Nielsen?

The National Provider Identifier (NPI) for Thomas Nielsen is 1235138546, a Type 1 (individual) record in the CMS NPPES registry.

Where does Thomas Nielsen practice?

The practice location on file with NPPES is in Chicago, IL. Providers can have multiple locations; NPPES lists the primary practice address.

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2011-05-04.