Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Gregory S Tierney, M.D.

Sports Medicine (Orthopaedic Surgery) Physician in Great Falls, MT · enumerated 2006.

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

National Provider Identifier

1679519870

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Registry record

Entity type Individual (Type 1)

Name Dr. Gregory S Tierney

Credential M.D.

Sex Male

Practice address 1401 25th St S, Great Falls, MT, 59405

Phone (406) 731-8888

Fax (406) 731-8876

Enumeration date Jun 22, 2006

Last updated in NPPES Apr 5, 2024

Taxonomy & licenses

207XX0005X Sports Medicine (Orthopaedic Surgery) Physician Allopathic & Osteopathic Physicians · License 7579 (MT) 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
000007501	Other	MT	BLUE CROSS BLUE SHIELD
200019136	Other	MT	RAILROAD MEDICARE
810347861008	Other	MT	EBMS
0103571	Medicaid	MT	-
0136986	Other	MT	WASHINGTON L&I
810347861	Other	MT	CHAMPUS

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 is the NPI number for Gregory Tierney?

The National Provider Identifier (NPI) for Gregory Tierney is 1679519870, a Type 1 (individual) record in the CMS NPPES registry.

Where does Gregory Tierney practice?

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

Other providers at this practice address

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2024-04-05.