Type 2 · Organization ✓ Active NPI ✓ Valid NPI checksum

Cornerstone Medical Group, LLC

Q: What is the NPI number for Cornerstone Medical Group, LLC?

The NPI for Cornerstone Medical Group, LLC is 1366797771, a Type 2 (organization) record in the CMS NPPES registry.

Primary Care Clinic/Center in Brookline, MA · enumerated 2012 · authorized official Jonathan Blumberg, Manager.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1366797771

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Registry record

Entity type Organization (Type 2)

Legal business name Cornerstone Medical Group, LLC

Practice address 1101 Beacon St, Suite 2 West, Brookline, MA, 02446

Phone (617) 775-7804

Enumeration date Jul 23, 2012

Last updated in NPPES Jul 23, 2012

Taxonomy & classification

261QP2300X Primary Care Clinic/Center Ambulatory Health Care Facilities · License 206504 (MA) Primary

Authorized official

Name Jonathan Blumberg

Title Manager

Phone (617) 775-7804

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

Who is the authorized official for Cornerstone Medical Group, LLC?

NPPES lists Jonathan Blumberg (Manager) as the authorized official for this organization.

What is the NPI number for Cornerstone Medical Group, LLC?

The NPI for Cornerstone Medical Group, LLC is 1366797771, a Type 2 (organization) record in the CMS NPPES registry.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2012-07-23.