Active NPI
Steven J Kassels, MD
- Internal Medicine Physician
- Westfield, MA
National Provider Identifier
1154458735
On this page
Key facts
NPPES NPI Registry- Primary specialty
- Internal Medicine Physician
- License
- 77240
- Practice address
- 125 N Elm St
Westfield, MA 01085-1643 - Phone
- (413) 568-6600
- NPI assigned
- Feb 28, 2007
- Sex
- Male
- Sole proprietor
- No
NPPES NPI Registry
Registry information is reported by the provider to CMS and is not verified. About this source
Specialties & licenses 2
| Specialty (taxonomy) | Code | License | State | Primary |
|---|---|---|---|---|
| Internal Medicine Physician | 207R00000X | 77240 | MA | Primary |
| Addiction Medicine (Internal Medicine) Physician | 207RA0401X | 77240 | MA |
Addresses
Primary practice location
125 N Elm St
Westfield, MA 01085-1643
Mailing address
125 North Elm Street
3Rd Floor
Westfield, MA 01085
Phone (413) 568-6600
Medicare participation
Medicare enrollment files- Medicare fee-for-service enrollment
- Not listed in the public Medicare enrollment file
National Provider Directory
National Provider Directory- Medicare enrollment (NPD)
- Not enrolled
- Credentials
- Doctor of Medicine
State licenses
| License | State | Type | Specialty |
|---|---|---|---|
| 77240 | MA | MD | Internal Medicine Physician |
NPI Registry JSON
The complete NPPES record for this NPI in the NPI Registry API format.
{
"created_epoch": "1172620800000",
"enumeration_type": "NPI-1",
"last_updated_epoch": "1757548800000",
"number": "1154458735",
"addresses": [
{
"country_code": "US",
"country_name": "United States",
"address_purpose": "MAILING",
"address_type": "DOM",
"address_1": "125 NORTH ELM STREET",
"address_2": "3RD FLOOR",
"city": "WESTFIELD",
"state": "MA",
"postal_code": "01085",
"telephone_number": "413-568-6600",
"fax_number": "413-562-8360"
},
{
"country_code": "US",
"country_name": "United States",
"address_purpose": "LOCATION",
"address_type": "DOM",
"address_1": "125 N ELM ST",
"city": "WESTFIELD",
"state": "MA",
"postal_code": "010851643",
"telephone_number": "413-568-6600"
}
],
"practiceLocations": [],
"basic": {
"last_name": "KASSELS",
"first_name": "STEVEN",
"middle_name": "J",
"name_prefix": "Mr.",
"credential": "MD",
"sole_proprietor": "NO",
"sex": "M",
"enumeration_date": "2007-02-28",
"last_updated": "2025-09-11",
"status": "A"
},
"taxonomies": [
{
"code": "207R00000X",
"taxonomy_group": "",
"desc": "Internal Medicine",
"state": "MA",
"license": "77240",
"primary": true
},
{
"code": "207RA0401X",
"taxonomy_group": "",
"desc": "Internal Medicine, Addiction Medicine",
"state": "MA",
"license": "77240",
"primary": false
}
],
"identifiers": [],
"endpoints": [],
"other_names": []
}Other providers in Westfield, MA
Sources for this page
- 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.