Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Mari Guillen, RN
Registered Nurse in Ojai, CA · enumerated 2023.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1366228884
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Registry record
Entity type Individual (Type 1)
Name Mari Guillen
Credential RN
Sex Female
Practice address 11496 N Ventura Ave, Ojai, CA, 93023
Phone (800) 748-3243
Enumeration date Aug 31, 2023
Last updated in NPPES Aug 31, 2023
Taxonomy & licenses
RN · Registered Nurse: A nurse who completed an accredited nursing program and passed the NCLEX-RN licensure exam.
About the RN 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.
Frequently asked questions
What specialty is Mari Guillen?
Mari Guillen is registered in NPPES with the primary taxonomy of Registered Nurse. 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.
Other providers at this practice address
Browse all →Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-08-31.