NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. Leonard Joseph Brennan, DMD

General Practice Dentistry in Portland, ME · enumerated 2007.

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

National Provider Identifier

1588844724

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)
Name Dr. Leonard Joseph Brennan
Credential DMD
Sex Male
Practice address Portland, ME, 04102
Phone (207) 773-2446
Fax (207) 773-4990
Enumeration date Nov 5, 2007
Last updated in NPPES Nov 5, 2007

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

1223G0001X General Practice Dentistry Dental Providers · License 2905 (ME) Primary
DMD · Doctor of Medicine in Dentistry: A licensed dentist; DMD and DDS are equivalent dental degrees. About the DMD credential

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

How do I verify Leonard Brennan's NPI record?
Cross-check NPI 1588844724 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.
Is NPI 1588844724 active?
Yes, as of the latest NPPES snapshot, NPI 1588844724 is active (record last updated 2007-11-05).

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-11-05.