Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Joanna Diel-Martin, NP

Nurse Practitioner in Petaluma, CA · enumerated 2019.

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

National Provider Identifier

1932759461

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Registry record

Entity type Individual (Type 1)

Name Joanna Diel-Martin

Credential NP

Sex Female

Practice address 1179 N Mcdowell Blvd, Petaluma, CA, 94954

Phone (707) 559-7500

Fax (707) 559-7620

Enumeration date Sep 17, 2019

Last updated in NPPES May 22, 2026

Taxonomy & licenses

363L00000X Nurse Practitioner Physician Assistants & Advanced Practice Nursing Providers · License 95012708 (CA) Primary

NP · Nurse Practitioner: An advanced practice registered nurse with graduate training, licensed to diagnose and treat, often with prescriptive authority. About the NP credential

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

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.

What specialty is Joanna Diel-Martin?

Joanna Diel-Martin is registered in NPPES with the primary taxonomy of Nurse Practitioner. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2026-05-22.