NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Mark Kevin Horowitz, DO

Dermatology Physician in Torrance, CA · enumerated 2006 · practices at Mark Horowitz Do, Inc..

Data current as of Jul 11, 2026 · sourced from CMS NPPES

National Provider Identifier

1669413878

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Registry record

Entity type Individual (Type 1)
Name Dr. Mark Kevin Horowitz
Credential DO
Sex Male
Practice address 23550 Hawthorne Blvd Ste 200, Torrance, CA, 90505
Phone (310) 373-2636
Enumeration date Jun 9, 2006
Last updated in NPPES Jan 17, 2014

Taxonomy & licenses

207N00000X Dermatology Physician Allopathic & Osteopathic Physicians · License 20A7642 (CA) Primary
207ND0101X MOHS-Micrographic Surgery Physician Allopathic & Osteopathic Physicians · License 20A7642 (CA) Secondary
207ND0900X Dermatopathology Physician Allopathic & Osteopathic Physicians · License 20A7642 (CA) Secondary
207NI0002X Clinical & Laboratory Dermatological Immunology Physician Allopathic & Osteopathic Physicians · License 20A7642 (CA) Secondary
207NP0225X Pediatric Dermatology Physician Allopathic & Osteopathic Physicians · License 20A7642 (CA) Secondary
207NS0135X Procedural Dermatology Physician Allopathic & Osteopathic Physicians · License 20A7642 (CA) Secondary
DO — Doctor of Osteopathic Medicine: A fully licensed physician trained in osteopathic medical schools, with the same practice rights as an MD. About the DO credential

Other identifiers

Identifier Type State Issuer
20A7642 Other CA OSTEOPATHIC MEDICAL BOARD

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

What specialty is Mark Horowitz?
Mark Horowitz is registered in NPPES with the primary taxonomy of Dermatology Physician. 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.

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Source: CMS NPPES (public data). Snapshot 2026-07-11. Provider record last updated 2014-01-17.