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

Dr. Marc Joshua Diener, PH.D.

Psychologist in Hewlett, NY · enumerated 2010.

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

National Provider Identifier

1255632337

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Registry record

Entity type Individual (Type 1)

Name Dr. Marc Joshua Diener

Credential PH.D.

Sex Male

Practice address Hewlett, NY, 11557

Phone (646) 246-1662

Fax (646) 871-0203

Enumeration date Nov 5, 2010

Last updated in NPPES Jul 10, 2013

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 68017465 (NY) Primary

103TC0700X Clinical Psychologist Behavioral Health & Social Service Providers · License 0810003955 (VA) Secondary

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.

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Frequently asked questions

Is NPI 1255632337 active?

Yes, as of the latest NPPES snapshot, NPI 1255632337 is active (record last updated 2013-07-10).

How do I verify Marc Diener's NPI record?

Cross-check NPI 1255632337 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2013-07-10.