Matthew Christopher Sies, M.D.

Primary specialty

Preventive Medicine/Occupational Environmental Medicine PhysicianTaxonomy code 2083P0500X

License

A81334 Issued in CA

Practice address

5525 W Slauson Ave
Los Angeles, CA 90056-1047

Phone

(310) 642-0325

Fax

(310) 642-0338

NPI assigned

May 9, 2007

Sex

Male

Sole proprietor

Yes

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

Specialties & licenses 2

Addresses

Other identifiers 1

Medicare fee-for-service enrollment

Not listed in the public Medicare enrollment file

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

State licenses

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

{
    "created_epoch": "1178668800000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1757548800000",
    "number": "1518171826",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "10824 LINDBROOK DR APT 320",
            "city": "LOS ANGELES",
            "state": "CA",
            "postal_code": "900248914",
            "telephone_number": "310-503-9474"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "5525 W SLAUSON AVE",
            "city": "LOS ANGELES",
            "state": "CA",
            "postal_code": "900561047",
            "telephone_number": "310-642-0325",
            "fax_number": "310-642-0338"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "SIES",
        "first_name": "MATTHEW",
        "middle_name": "CHRISTOPHER",
        "credential": "M.D.",
        "sole_proprietor": "YES",
        "sex": "M",
        "enumeration_date": "2007-05-09",
        "last_updated": "2025-09-11",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "2083P0500X",
            "taxonomy_group": "",
            "desc": "Preventive Medicine, Preventive Medicine/Occupational Environmental Medicine",
            "state": "CA",
            "license": "A81334",
            "primary": true
        },
        {
            "code": "208D00000X",
            "taxonomy_group": "",
            "desc": "General Practice",
            "state": "CA",
            "license": "A81334",
            "primary": false
        }
    ],
    "identifiers": [
        {
            "code": "01",
            "desc": "Other (non-Medicare)",
            "issuer": "PPIN",
            "identifier": "WA81334A",
            "state": "CA"
        }
    ],
    "endpoints": [],
    "other_names": []
}

• Maria Esther Sierra
• Morena Guadalupe Sierra
• Tiffany Rae Sierra, LVN
• William Sierra, M.D.
• Kenneth Scott Siers, LCSW
• Theodore Martens Sievers, PHARM.D.
• Diana Ann Siew
• Hector Sifontes
• Keyla Camille Sifre, REGISTERED DIETITIAN
• Romina Sifuentes Palomino, M.D.

• Preventive Medicine/Occupational Environmental Medicine Physician in Los Angeles, CA
• Providers in Los Angeles, CA by specialty
• Preventive Medicine/Occupational Environmental Medicine Physician in California

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Sep 11, 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.