Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

William P Klein, MD

Internal Medicine Physician in Newport Beach, CA · enumerated 2005.

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

National Provider Identifier

1205834819

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Registry record

Entity type Individual (Type 1)

Name William P Klein

Credential MD

Sex Male

Practice address 1501 Superior Ave, #111, Newport Beach, CA, 92663

Phone (949) 274-8030

Fax (949) 642-3127

Enumeration date Jul 8, 2005

Last updated in NPPES Jan 17, 2008

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License G14712 (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
00G147120	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

Where does William Klein practice?

The practice location on file with NPPES is in Newport Beach, CA. Providers can have multiple locations; NPPES lists the primary practice address.

What is the NPI number for William Klein?

The National Provider Identifier (NPI) for William Klein is 1205834819, a Type 1 (individual) record in the CMS NPPES registry.

Other providers at this practice address

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2008-01-17.