Stephen F Mast, L.M.S.W.

Primary specialty

Social WorkerTaxonomy code 104100000X

License

081999-1 Issued in NY

Practice address

93 Main St
Suite 1J
West Sayville, NY 11796

Phone

(631) 502-5220

Fax

(631) 256-9353

NPI assigned

Oct 20, 2010

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

Not listed in the public Medicare enrollment file

Medicare enrollment (NPD)

Not enrolled

State licenses

Practice roles

Locations

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.

• Innovations Counseling, LCSW PLLC

  • Clinical Social Worker
  • West Sayville, NY
  • NPI 1568902062
  NPD
• Sardonyx Wellness LCSW PLLC

  • Clinical Social Worker
  • West Sayville, NY
  • NPI 1477210698
  NPD

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

{
    "created_epoch": "1287532800000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1757980800000",
    "number": "1558671735",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "9525 QUEENS BLVD STE 812",
            "city": "REGO PARK",
            "state": "NY",
            "postal_code": "113744522",
            "telephone_number": "718-896-6500",
            "fax_number": "347-868-6427"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "93 MAIN ST",
            "address_2": "SUITE 1J",
            "city": "WEST SAYVILLE",
            "state": "NY",
            "postal_code": "11796",
            "telephone_number": "631-502-5220",
            "fax_number": "631-256-9353"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "MAST",
        "first_name": "STEPHEN",
        "middle_name": "F",
        "credential": "L.M.S.W.",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2010-10-20",
        "last_updated": "2025-09-16",
        "certification_date": "2025-09-16",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "104100000X",
            "taxonomy_group": "",
            "desc": "Social Worker",
            "state": "NY",
            "license": "081999-1",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

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• Social Worker in West Sayville, NY
• Providers in West Sayville, NY by specialty
• Social Worker in New York

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Sep 16, 2025; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.