Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Steven C. Thornquist, M.D.

Pediatric Ophthalmology and Strabismus Specialist Physician in Waterbury, CT · enumerated 2006.

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

National Provider Identifier

1558441378

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)

Name Dr. Steven C. Thornquist

Credential M.D.

Sex Male

Practice address 1201 W Main St Ste 100, Waterbury, CT, 06708

Phone (203) 597-9100

Fax (203) 573-4805

Enumeration date Oct 16, 2006

Last updated in NPPES Mar 17, 2018

Taxonomy & licenses

207W00000X Ophthalmology Physician Allopathic & Osteopathic Physicians · License 031010 (CT) Secondary

207WX0110X Pediatric Ophthalmology and Strabismus Specialist Physician Allopathic & Osteopathic Physicians · License 031010 (CT) Primary

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
5741404	Other	CT	AETNA

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 Steven Thornquist?

The National Provider Identifier (NPI) for Steven Thornquist is 1558441378, a Type 1 (individual) record in the CMS NPPES registry.

Where does Steven Thornquist practice?

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

Other providers at this practice address

Browse all →

Angela Bosjolie Ophthalmology Physician · Waterbury, CT NPI 1093891608 Alexander Nguyen Ophthalmology Physician · Waterbury, CT NPI 1619316395 Meredith Kim Ophthalmology Physician · Waterbury, CT NPI 1700311248 Jillian Kaplita Ophthalmology Physician · Waterbury, CT NPI 1386148070 Airi Ando Optometrist · Waterbury, CT NPI 1316517048

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2018-03-17.