Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Benjamin Siemanowski, M.D.

Gastroenterology Physician in Bellingham, WA · enumerated 2007 · practices at Northwest Gastroenterology Professional LLC.

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

National Provider Identifier

1548301120

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Registry record

Entity type Individual (Type 1)

Name Benjamin Siemanowski

Credential M.D.

Sex Male

Practice address 3111 Woburn St Ste 201, Bellingham, WA, 98226

Phone (360) 734-1420

Fax (360) 733-1659

Enumeration date Feb 8, 2007

Last updated in NPPES May 24, 2023

Taxonomy & licenses

207RG0100X Gastroenterology Physician Allopathic & Osteopathic Physicians · License MD00047499 (WA) 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
7201924	Other	WA	AETNA
1548301120	Medicaid	WA	-
2854SI	Other	WA	REGENCE
0229984	Other	WA	L&I AND CRIME VICTIMS

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 is the NPI number for Benjamin Siemanowski?

The National Provider Identifier (NPI) for Benjamin Siemanowski is 1548301120, a Type 1 (individual) record in the CMS NPPES registry.

Where does Benjamin Siemanowski practice?

The practice location on file with NPPES is in Bellingham, WA. 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 2023-05-24.