Tomas Gerald Neilan, MD

Primary specialty

Cardiovascular Disease PhysicianTaxonomy code 207RC0000X

License

234637 Issued in MA

Practice address

Massachusetts General Hospital
55 Fruit Street
Boston, MA 02114

Phone

(617) 724-2700

NPI assigned

Feb 26, 2007

Sex

Male

Sole proprietor

No

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

Specialties & licenses 2

Addresses

Other identifiers 1

Other names 1

• Dr. Tomas Gerald Neilan Professional name

Medicare fee-for-service enrollment

Enrolled in MA

Eligible to order & refer

• Part B services: Yes
• Medical equipment: Yes
• Home health: Yes
• Power mobility devices: Yes
• Hospice: Yes

Green means eligible to order or refer.

Enrollment records 1

Specialty

Cardiovascular Disease (Cardiology)Also: Internal Medicine

Education

Other, 1996

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Telehealth

Offers telehealth services

Group practices

Massachusetts General Physicians Organization IncGroup PAC ID 2466365820, 3,494 clinicians

The General Hospital CorporationGroup PAC ID 6507803806, 1,275 clinicians

Practice addresses (Care Compare)

Hospital & facility affiliations

• Massachusetts General Hospital Hospital, Boston, MA, CCN 220071
• North Shore Medical Center - Hospital, Salem, MA, CCN 220035
• Brigham and Women'S Hospital Hospital, Boston, MA, CCN 220110
• Newton-Wellesley Hospital Hospital, Newton, MA, CCN 220101
• Winchester Hospital Hospital, Winchester, MA, CCN 220105

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

Practice roles

Locations

Interoperability endpoints

• Direct secure messaging: neilan.tomas.mgh@direct.partners.masshiway.net

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.

• Massachusetts General Physicians Organization Inc

  • Dermatology Physician
  • Boston, MA
  • NPI 1801874573

  Internal Medicine

  Medicare reassignment Care Compare group NPD
• The General Hospital Corporation

  • General Acute Care Hospital
  • Boston, MA
  • NPI 1023049236
  Medicare reassignment Care Compare group NPD
• Brigham & Womens Physicians Organization Inc

  • Internal Medicine Physician
  • Boston, MA
  • NPI 1033535497
  Medicare reassignment NPD
• Mass General Brigham Medical Group Suburban Massachusetts Inc

  • Family Medicine Physician
  • Newton, MA
  • NPI 1538191218
  Medicare reassignment NPD
• General Hospital Corp

  • General Acute Care Hospital
  • Boston, MA
  • NPI 1508390014
  NPD

Hospitals and other facilities this clinician is affiliated with according to Medicare Care Compare.

• Brigham & Womens Hospital, Inc.

  • General Acute Care Hospital
  • Boston, MA
  • NPI 1790717650
  Care Compare affiliation
• Newton-Wellesley Hospital

  • General Acute Care Hospital
  • Newton, MA
  • NPI 1992737761
  Care Compare affiliation
• North Shore Medical Center, Inc.

  • General Acute Care Hospital
  • Salem, MA
  • NPI 1730121633
  Care Compare affiliation
• The General Hospital Corporation

  • General Acute Care Hospital
  • Boston, MA
  • NPI 1023049236
  Care Compare affiliation
• Winchester Hospital

  • General Acute Care Hospital
  • Winchester, MA
  • NPI 1790740777
  Care Compare affiliation

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

{
    "created_epoch": "1172448000000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1767398400000",
    "number": "1437285145",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "55 FRUIT ST",
            "city": "BOSTON",
            "state": "MA",
            "postal_code": "021142621",
            "telephone_number": "617-724-2700"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "MASSACHUSETTS GENERAL HOSPITAL",
            "address_2": "55 FRUIT STREET",
            "city": "BOSTON",
            "state": "MA",
            "postal_code": "02114",
            "telephone_number": "617-724-2700"
        }
    ],
    "practiceLocations": [
        {
            "address_1": "75 Francis St",
            "address_purpose": "LOCATION",
            "city": "Boston",
            "state": "MA",
            "postal_code": "021156106",
            "country_code": "US",
            "telephone_number": "617-732-5500",
            "country_name": "United States",
            "address_type": "DOM"
        }
    ],
    "basic": {
        "last_name": "NEILAN",
        "first_name": "TOMAS",
        "middle_name": "GERALD",
        "name_prefix": "Dr.",
        "credential": "MD",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2007-02-26",
        "last_updated": "2026-01-03",
        "certification_date": "2026-01-03",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207RC0000X",
            "taxonomy_group": "",
            "desc": "Internal Medicine, Cardiovascular Disease",
            "state": "MA",
            "license": "234637",
            "primary": true
        },
        {
            "code": "207R00000X",
            "taxonomy_group": "",
            "desc": "Internal Medicine",
            "state": "MA",
            "license": "234637",
            "primary": false
        }
    ],
    "identifiers": [
        {
            "code": "05",
            "desc": "MEDICAID",
            "issuer": null,
            "identifier": "110088962A",
            "state": "MA"
        }
    ],
    "endpoints": [],
    "other_names": [
        {
            "first_name": "TOMAS",
            "last_name": "NEILAN",
            "middle_name": "GERALD",
            "prefix": "DR.",
            "credential": "MD",
            "code": "2",
            "type": "Professional Name"
        }
    ]
}

• Neighborhood Home Health Care Inc
• Alexander J Neil, MD
• Kayli Neil
• Anne Maryjo Neilan, M.D., M.P.H
• Edward G Neilan, MD, PHD
• Sara N. Neill, M.D.
• Maegan Rose Neilson
• Kathleen Joyce Neimann, N.P.
• Jacob Louis Neir, MD
• Larissa Nekhlyudov, M.D.

• Cardiovascular Disease Physician in Boston, MA
• Providers in Boston, MA by specialty
• Cardiovascular Disease Physician in Massachusetts

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Jan 3, 2026; 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.