Guillermo Diaz, NP-P

Primary specialty

Psychiatric/Mental Health Nurse PractitionerTaxonomy code 363LP0808X

License

402068 Issued in NY

Practice address

185 W John St # 113
Hicksville, NY 11801-1007

Phone

(646) 856-9971

Fax

(516) 531-8539

NPI assigned

Jul 29, 2016

Sex

Male

Sole proprietor

No

Registry information is reported by the provider to CMS and is not verified. About this source

Specialties & licenses 1

Addresses

Medicare fee-for-service enrollment

Enrolled in NY, CT, CO3 enrollments

Eligible to order & refer

• Part B services: Yes
• Medical equipment: Yes
• Home health: Yes
• Power mobility devices: Yes
• Hospice: No

Green means eligible to order or refer.

Enrollment records 3

Specialty

Nurse Practitioner

Education

Other, 2016

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Telehealth

Offers telehealth services

Practice addresses (Care Compare)

Medicare enrollment (NPD)

Enrolled

Practice roles

Locations

Networks

• Healthfirst Medicare Network H5989
• Healthfirst Medicare Network H3359
• Healthfirst Medicare Network H1722
• Healthfirst Medicare Network H9678

Interoperability endpoints

• Direct secure messaging: gdiaz@landmarkhealth-direct.org

Organizations this provider is connected to: Medicare benefit reassignments (the organization bills Medicare for this provider’s services), Care Compare group memberships and National Provider Directory roles.

• Grow Healthcare Group PA

  • Mental Health Counselor
  • Miami, FL
  • NPI 1245845932

  CO, CT, NY, Psychiatric/Mental Health

  Medicare reassignment NPD
• Wagner Medical PC

  • Clinical Social Worker
  • Toms River, NJ
  • NPI 1235951187

  NY, Psychiatric/Mental Health

  Medicare reassignment NPD

The complete NPPES record for this NPI in the NPI Registry API format.

{
    "created_epoch": "1469750400000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1757030400000",
    "number": "1164975801",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "185 W JOHN ST # 113",
            "city": "HICKSVILLE",
            "state": "NY",
            "postal_code": "118011007",
            "telephone_number": "646-856-9971",
            "fax_number": "516-531-8539"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "185 W JOHN ST # 113",
            "city": "HICKSVILLE",
            "state": "NY",
            "postal_code": "118011007",
            "telephone_number": "646-856-9971",
            "fax_number": "516-531-8539"
        }
    ],
    "practiceLocations": [
        {
            "address_1": "1985 Marcus Ave Ste 110",
            "address_purpose": "LOCATION",
            "city": "New Hyde Park",
            "state": "NY",
            "postal_code": "110422024",
            "country_code": "US",
            "telephone_number": "855-201-4988",
            "country_name": "United States",
            "address_type": "DOM"
        }
    ],
    "basic": {
        "last_name": "DIAZ",
        "first_name": "GUILLERMO",
        "credential": "NP-P",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2016-07-29",
        "last_updated": "2025-09-05",
        "certification_date": "2025-09-05",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "363LP0808X",
            "taxonomy_group": "",
            "desc": "Nurse Practitioner, Psychiatric/Mental Health",
            "state": "NY",
            "license": "402068",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

• Elizabeth Devine, MA
• Alison Marie Devitt, PA-C
• Ashleigh Devivo
• Natalia Cristina Dias
• Elyse Nicole Diaz
• Sarabeth Dicostanzo, LPC
• Leeann Diedrick, LCSW
• Kayla Elizabeth Dignan, BA
• Ukuku Kulu Dike, MD
• Colleen Erin Dilello

• Psychiatric/Mental Health Nurse Practitioner in Hicksville, NY
• Providers in Hicksville, NY by specialty
• Psychiatric/Mental Health Nurse Practitioner in New York

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Sep 5, 2025; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments; Order and Referring.
• Medicare Care Compare (CMS): clinician profile, group practices, facility affiliations, MIPS scores and star ratings.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.