Active NPI
Matthew Samuel Loewenstein, MD
- Gastroenterology Physician
- Cambridge, MA
National Provider Identifier
1215904982
On this page
Key facts
NPPES NPI Registry- Primary specialty
- Gastroenterology Physician
- License
- 35973
- Practice address
- 300 Mt Auburn St
Suite 507
Cambridge, MA 02238 - Phone
- (617) 876-5674
- Fax
- (617) 661-7640
- NPI assigned
- Mar 2, 2006
- Last updated
- Jul 13, 2026
- 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 1
| Specialty (taxonomy) | Code | License | State | Primary |
|---|---|---|---|---|
| Gastroenterology Physician | 207RG0100X | 35973 | MA | Primary |
Addresses
Primary practice location
300 Mt Auburn St
Suite 507
Cambridge, MA 02238
Mailing address
300 Mt Auburn St
Suite 507
Cambridge, MA 02238
Phone (617) 876-5674
Other identifiers 3
| Identifier | Type | State | Issuer |
|---|---|---|---|
| 0163015 | Medicaid | MA | |
| B53083 | Other | MA | BLUE CROSS |
| 035973 | Other | MA | TUFTS |
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)
- Enrolled
- Credentials
- Doctor of Medicine
Practice roles
| Organization | Specialty | Status | New patients |
|---|---|---|---|
| Matthew S. Loewenstein, MD | Gastroenterology | Past | Accepting new patients |
Organizations & group practices 1
Organizations this provider is connected to: Medicare benefit reassignments (the organization bills Medicare for this provider’s services), Care Compare group memberships, National Provider Directory roles and organizations whose NPPES authorized official is this provider.
-
dba Cambridge Gastroenterology Associates
- Gastroenterology Physician
- Cambridge, MA
- NPI 1750598652
NPI Registry JSON
The complete NPPES record for this NPI in the NPI Registry API format.
{
"created_epoch": "1141257600000",
"enumeration_type": "NPI-1",
"last_updated_epoch": "1783900800000",
"number": "1215904982",
"addresses": [
{
"country_code": "US",
"country_name": "United States",
"address_purpose": "MAILING",
"address_type": "DOM",
"address_1": "300 MT AUBURN ST",
"address_2": "SUITE 507",
"city": "CAMBRIDGE",
"state": "MA",
"postal_code": "02238",
"telephone_number": "617-876-5674",
"fax_number": "617-661-7640"
},
{
"country_code": "US",
"country_name": "United States",
"address_purpose": "LOCATION",
"address_type": "DOM",
"address_1": "300 MT AUBURN ST",
"address_2": "SUITE 507",
"city": "CAMBRIDGE",
"state": "MA",
"postal_code": "02238",
"telephone_number": "617-876-5674",
"fax_number": "617-661-7640"
}
],
"practiceLocations": [],
"basic": {
"last_name": "LOEWENSTEIN",
"first_name": "MATTHEW",
"middle_name": "SAMUEL",
"name_prefix": "Dr.",
"credential": "MD",
"sole_proprietor": "NO",
"sex": "M",
"enumeration_date": "2006-03-02",
"last_updated": "2026-07-13",
"status": "A"
},
"taxonomies": [
{
"code": "207RG0100X",
"taxonomy_group": "",
"desc": "Internal Medicine, Gastroenterology",
"state": "MA",
"license": "35973",
"primary": true
}
],
"identifiers": [
{
"code": "05",
"desc": "MEDICAID",
"issuer": null,
"identifier": "0163015",
"state": "MA"
},
{
"code": "01",
"desc": "Other (non-Medicare)",
"issuer": "BLUE CROSS",
"identifier": "B53083",
"state": "MA"
},
{
"code": "01",
"desc": "Other (non-Medicare)",
"issuer": "TUFTS",
"identifier": "035973",
"state": "MA"
}
],
"endpoints": [],
"other_names": []
}Other providers in Cambridge, MA
Sources for this page
- NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Jul 13, 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.