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

Gregory H. Tchejeyan, M.D., INC

Specialist in Thousand Oaks, CA · enumerated 2005.

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

National Provider Identifier

1689668188

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Registry record

Entity type Individual (Type 1)

Name Gregory H. Tchejeyan

Credential M.D., INC

Sex Male

Practice address Thousand Oaks, CA, 91360

Phone (805) 495-3687

Fax (805) 494-1828

Enumeration date Sep 12, 2005

Last updated in NPPES Mar 29, 2022

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

Taxonomy & licenses

174400000X Specialist Other Service Providers · License A55364 (CA) 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
1376835330	Other	CA	NPI TYPE II

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

What specialty is Gregory Tchejeyan?

Gregory Tchejeyan is registered in NPPES with the primary taxonomy of Specialist. 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 2022-03-29.