Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Steven Mattis, PH.D.

Psychologist in White Plains, NY · enumerated 2007.

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

National Provider Identifier

1285839324

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Registry record

Entity type Individual (Type 1)

Name Dr. Steven Mattis

Credential PH.D.

Sex Male

Practice address 34 S Broadway, Suite 100, White Plains, NY, 10601

Phone (914) 997-5151

Fax (914) 997-0333

Enumeration date Jun 19, 2007

Last updated in NPPES Jul 8, 2007

Taxonomy & licenses

103T00000X Psychologist Behavioral Health & Social Service Providers · License 003294-0 (NY) Primary

PHD · Doctor of Philosophy: A doctoral degree; in healthcare often held by clinical psychologists and researchers. About the PHD 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

What is the NPI number for Steven Mattis?

The National Provider Identifier (NPI) for Steven Mattis is 1285839324, a Type 1 (individual) record in the CMS NPPES registry.

Where does Steven Mattis practice?

The practice location on file with NPPES is in White Plains, NY. 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 2007-07-08.