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Stephen Louis Walston, MD

Internal Medicine Physician in Mercer Island, WA · enumerated 2010.

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

National Provider Identifier

1578887519

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Registry record

Entity type Individual (Type 1)
Name Stephen Louis Walston
Credential MD
Sex Male
Practice address 3236 78th Ave Se Ste 200, Mercer Island, WA, 98040
Phone (206) 386-9500
Fax (206) 386-9605
Enumeration date Mar 19, 2010
Last updated in NPPES Nov 11, 2021

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License MD60423761 (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
1578887519 Medicaid WA -
2022131 Medicaid WA -

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

Where does Stephen Walston practice?
The practice location on file with NPPES is in Mercer Island, WA. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Stephen Walston?
The National Provider Identifier (NPI) for Stephen Walston is 1578887519, a Type 1 (individual) record in the CMS NPPES registry.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2021-11-11.