Type 2 · Organization ✓ Active NPI ✓ Valid NPI checksum

Leon J. Kosek, O.D.

Optometrist in Frankfort, IL · enumerated 2007 · authorized official Leon Kosek, Owner.

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

National Provider Identifier

1407975782

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Registry record

Entity type Organization (Type 2)

Legal business name Leon J. Kosek, O.D.

Practice address 600 Bankview Dr, Frankfort, IL, 60423

Phone (815) 469-8541

Fax (815) 469-8126

Enumeration date Mar 28, 2007

Last updated in NPPES Dec 31, 2009

Taxonomy & classification

152W00000X Optometrist Eye and Vision Services Providers · License 046007472 (IL) Primary

Authorized official

Name Leon Kosek

Title Owner

Phone (815) 469-8541

Other identifiers

Identifier	Type	State	Issuer
09922174	Other	IL	BLUE CROSS/BLUE SHIELD

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

Where is Leon J. Kosek, O.D. located?

The practice location on file with NPPES is in Frankfort, IL.

How current is this record?

Data comes from the CMS NPPES public dissemination file; this record was last updated in NPPES on 2009-12-31. Verify at npiregistry.cms.hhs.gov.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2009-12-31.