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Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. Themis Yiaslas, PSY.D.

Psychologist in Mather, CA · enumerated 2012.

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

National Provider Identifier

1144573171

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Registry record

Entity type Individual (Type 1)
Name Dr. Themis Yiaslas
Credential PSY.D.
Sex Male
Practice address Mather, CA, 95655
Phone (916) 366-5420
Enumeration date Oct 15, 2012
Last updated in NPPES Oct 15, 2012

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

103T00000X Psychologist Behavioral Health & Social Service Providers · License 25305 (CA) Primary
PSYD · Doctor of Psychology: A clinical doctorate in psychology focused on professional practice. About the PSYD 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.

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Frequently asked questions

Where does Themis Yiaslas practice?
The practice location on file with NPPES is in Mather, CA. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Themis Yiaslas?
The National Provider Identifier (NPI) for Themis Yiaslas is 1144573171, a Type 1 (individual) record in the CMS NPPES registry.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2012-10-15.