NPI Portal NPI Lookup & Verification

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

Dr. Mark Robert Windt, M.D.

Allergy & Immunology Physician in North Hampton, NH · enumerated 2006.

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

National Provider Identifier

1689625600

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Registry record

Entity type Individual (Type 1)
Name Dr. Mark Robert Windt
Credential M.D.
Sex Male
Practice address North Hampton, NH, 03862
Phone (603) 964-3392
Fax (603) 964-3396
Enumeration date May 15, 2006
Last updated in NPPES Jul 9, 2007

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

Taxonomy & licenses

207K00000X Allergy & Immunology Physician Allopathic & Osteopathic Physicians · License 7208 (NH) Primary
MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier Type State Issuer
30008459 Medicaid NH -

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 Mark Windt?
The National Provider Identifier (NPI) for Mark Windt is 1689625600, a Type 1 (individual) record in the CMS NPPES registry.
Where does Mark Windt practice?
The practice location on file with NPPES is in North Hampton, NH. 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 2007-07-09.