NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Nicholas Junhyuk Ahn, M.D.

Surgery Physician in Stony Brook, NY · enumerated 2013.

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

National Provider Identifier

1912341447

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Registry record

Entity type Individual (Type 1)
Name Nicholas Junhyuk Ahn
Credential M.D.
Sex Male
Practice address Stony Brook, NY, 11794
Phone (631) 444-1791
Enumeration date Apr 26, 2013
Last updated in NPPES Sep 7, 2021

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

390200000X Student in an Organized Health Care Education/Training Program Student, Health Care · License 63283 Secondary
390200000X Student in an Organized Health Care Education/Training Program Student, Health Care Secondary
208600000X Surgery Physician Allopathic & Osteopathic Physicians · License 306605 (NY) Primary
MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

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.

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Frequently asked questions

Where does Nicholas Ahn practice?
The practice location on file with NPPES is in Stony Brook, NY. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Nicholas Ahn?
The National Provider Identifier (NPI) for Nicholas Ahn is 1912341447, a Type 1 (individual) record in the CMS NPPES registry.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2021-09-07.