Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Walter J Nalesnik Jr., MD

Internal Medicine Physician in Lynn, MA · enumerated 2006 · practices at Robert R Pennell MD PC.

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

National Provider Identifier

1376616029

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Registry record

Entity type Individual (Type 1)

Name Walter J Nalesnik Jr.

Credential MD

Sex Male

Practice address 225 Boston Street, 204, Lynn, MA, 01904

Phone (781) 595-9581

Fax (781) 595-9628

Enumeration date Nov 17, 2006

Last updated in NPPES Jul 10, 2007

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License S3680 (MA) 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
703505	Other	-	TUFTS
65494	Other	-	HPHC
9037	Other	-	US HEALTH
80744	Other	-	FALLON
J04507	Other	-	BCBS
0400048	Other	-	UNITED
9705121	Medicaid	MA	-
B1002301	Other	-	CIGNA

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

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.

What specialty is Walter Nalesnik?

Walter Nalesnik 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.

Other providers at this practice address

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Robert R Pennell MD PC Orthopaedic Surgery Physician · Lynn, MA NPI 1306031612

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-07-10.