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Stephen Anthony Weller, MD

Radiation Oncology Physician in Mountain View, CA · enumerated 2005.

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

National Provider Identifier

1154312890

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Registry record

Entity type Individual (Type 1)
Name Stephen Anthony Weller
Credential MD
Sex Male
Practice address 701 E. El Camino Real, Mountain View, CA, 94040
Phone (650) 934-7000
Enumeration date Nov 2, 2005
Last updated in NPPES Mar 16, 2016

Taxonomy & licenses

2085R0001X Radiation Oncology Physician Allopathic & Osteopathic Physicians · License C34851 (CA) 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
00C348510 Other CA BLUE SHIELD
00C348510 Medicaid CA -

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 Stephen Weller?
Stephen Weller is registered in NPPES with the primary taxonomy of Radiation Oncology 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.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2016-03-16.