Connor James O'Brien, MD

Primary specialty

Hospitalist PhysicianTaxonomy code 208M00000X

License

A198979 Issued in CA

Practice address

101 The City Dr S Ste 400
Orange, CA 92868-3201

Phone

(714) 456-5691

NPI assigned

Mar 28, 2023

Sex

Male

Sole proprietor

Yes

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

Credentials

Doctor of Medicine

Practice roles

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.

• The Regents of the University of California-Irvine

  • Hospitalist Physician
  • Orange, CA
  • NPI 1154479723
  NPD (past)

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

{
    "created_epoch": "1679961600000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1788912000000",
    "number": "1457055964",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "104 PRESERVE",
            "city": "IRVINE",
            "state": "CA",
            "postal_code": "926184804"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "101 THE CITY DR S STE 400",
            "city": "ORANGE",
            "state": "CA",
            "postal_code": "928683201",
            "telephone_number": "714-456-5691"
        }
    ],
    "practiceLocations": [
        {
            "address_1": "400 N McDowell Blvd",
            "address_purpose": "LOCATION",
            "city": "Petaluma",
            "state": "CA",
            "postal_code": "949542339",
            "country_code": "US",
            "telephone_number": "707-303-1709",
            "fax_number": "707-303-3912",
            "country_name": "United States",
            "address_type": "DOM"
        }
    ],
    "basic": {
        "last_name": "O'BRIEN",
        "first_name": "CONNOR",
        "middle_name": "JAMES",
        "credential": "MD",
        "sole_proprietor": "YES",
        "sex": "M",
        "enumeration_date": "2023-03-28",
        "last_updated": "2026-09-09",
        "certification_date": "2026-09-09",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "208M00000X",
            "taxonomy_group": "",
            "desc": "Hospitalist",
            "state": "CA",
            "license": "A198979",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

• David Nykin
• Melanie Lorraine Nyland
• Thaddeus O'Barr IV, M.D.
• Brandon J O'Brien, R.R.T.
• Brianna Nicole O'Brien
• Gianmarco O'Brien, D.D.S.
• Susan M. O'Brien, M.D.
• Cameron O'Connell, DO
• Patricia Kay O'Connell
• Ryan O'Connell, M.D.

• Hospitalist Physician in Orange, CA
• Providers in Orange, CA by specialty
• Hospitalist Physician in California

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Sep 9, 2026; 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.