Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Mark A. Walker, M.D.

Internal Medicine Physician in Gallipolis, OH · enumerated 2006 · practices at Holzer Hospital Foundation.

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

National Provider Identifier

1538196662

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)

Name Mark A. Walker

Credential M.D.

Sex Male

Practice address 90 Jackson Pike, Gallipolis, OH, 45631

Phone (740) 446-5131

Fax (740) 446-5486

Enumeration date Jun 26, 2006

Last updated in NPPES Mar 5, 2011

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 35-04-7305 (OH) Primary

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 15377 (WV) Secondary

207RX0202X Medical Oncology Physician Allopathic & Osteopathic Physicians · License 35-04-7305 (OH) Secondary

207RX0202X Medical Oncology Physician Allopathic & Osteopathic Physicians · License 15377 (WV) Secondary

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
900000134	Other	OH	RR MEDICARE
000000181881	Other	OH	UNISON MEDICAID #
0083691000	Medicaid	WV	-
000000006739	Other	-	ANTHEM BCBS
0488628	Other	OH	MOLINA MEDICAID #
001714036	Other	-	MOUNTAIN STATE BCBS
0488628	Medicaid	OH	-
310917085096	Other	OH	CARESOURCE MEDICAID #

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 Mark Walker?

Mark Walker 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.

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2011-03-05.