Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Susan M. O'Brien, M.D.

Medical Oncology Physician in Orange, CA · enumerated 2006.

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

National Provider Identifier

1669577276

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Registry record

Entity type Individual (Type 1)

Name Susan M. O'Brien

Credential M.D.

Sex Female

Practice address 101 the City Drive South, Bldg. 23, Rm. 403, Orange, CA, 92868

Phone (714) 456-8000

Fax (714) 456-3810

Enumeration date Sep 14, 2006

Last updated in NPPES Jun 6, 2019

Taxonomy & licenses

207RX0202X Medical Oncology Physician Allopathic & Osteopathic Physicians · License H3130 (TX) 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
800947	Other	TX	BCBS
100519101	Medicaid	TX	-
110059114	Other	TX	RR MEDICARE

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 Susan O'Brien?

The National Provider Identifier (NPI) for Susan O'Brien is 1669577276, a Type 1 (individual) record in the CMS NPPES registry.

Where does Susan O'Brien practice?

The practice location on file with NPPES is in Orange, CA. 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 2019-06-06.