Type 2 · Organization ✓ Active NPI ✓ Valid NPI checksum

Mark Greenstadt, M.D., Inc.

Q: What is the NPI number for Mark Greenstadt, M.D., Inc.?

The NPI for Mark Greenstadt, M.D., Inc. is 1770635120, a Type 2 (organization) record in the CMS NPPES registry.

Internal Medicine Physician in Northridge, CA · enumerated 2007 · authorized official Mark Greenstadt, President.

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

National Provider Identifier

1770635120

Verified

See something wrong? Report a correction

Registry record

Entity type Organization (Type 2)

Legal business name Mark Greenstadt, M.D., Inc.

Practice address 18350 Roscoe Blvd, Suite 300, Northridge, CA, 91325

Phone (818) 717-3021

Fax (818) 717-3028

Enumeration date Jan 17, 2007

Last updated in NPPES Aug 22, 2020

Taxonomy & classification

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License G35141 (CA) Primary

Authorized official

Name Mark Greenstadt

Title President

Phone (818) 717-3021

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

What is the NPI number for Mark Greenstadt, M.D., Inc.?

The NPI for Mark Greenstadt, M.D., Inc. is 1770635120, a Type 2 (organization) record in the CMS NPPES registry.

Who is the authorized official for Mark Greenstadt, M.D., Inc.?

NPPES lists Mark Greenstadt (President) as the authorized official for this organization.

Providers at this address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2020-08-22.