NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Frank J Kessler, M.D.

Internal Medicine Physician in Brewster, NY · enumerated 2006 · practices at Eastern New York Medical Services PC.

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

National Provider Identifier

1679500086

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Registry record

Entity type Individual (Type 1)
Name Frank J Kessler
Credential M.D.
Sex Male
Practice address 3423 Danbury Rd, Brewster, NY, 10509
Phone (845) 279-7200
Enumeration date Jun 28, 2006
Last updated in NPPES Sep 17, 2020

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 026499 (CT) Secondary
207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 165978 (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.

Read the full guide → Validate an NPI →

Frequently asked questions

What specialty is Frank Kessler?
Frank Kessler is registered in NPPES with the primary taxonomy of Internal Medicine Physician. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.
Is this the official NPI registry?
No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2020-09-17.