Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Walter M O'Brien, MD

Urology Physician in Leesburg, VA · enumerated 2005 · practices at Loudoun Medical Group, PC.

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

National Provider Identifier

1730173360

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Registry record

Entity type Individual (Type 1)

Name Dr. Walter M O'Brien

Credential MD

Sex Male

Practice address 19415 Deerfield Avenue, Suite 112, Leesburg, VA, 20176

Phone (703) 724-1195

Fax (703) 724-4495

Enumeration date Sep 9, 2005

Last updated in NPPES Jan 10, 2024

Taxonomy & licenses

208800000X Urology Physician Allopathic & Osteopathic Physicians · License 0101038671 (VA) Primary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier	Type	State	Issuer
1730173360	Medicaid	VA	-
7503300	Medicaid	VA	-
340018240	Other	DC	RR MEDICARE
7503326	Medicaid	VA	-
340017880	Other	VA	RRMEDICARE

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 Walter O'Brien?

The National Provider Identifier (NPI) for Walter O'Brien is 1730173360, a Type 1 (individual) record in the CMS NPPES registry.

Where does Walter O'Brien practice?

The practice location on file with NPPES is in Leesburg, VA. Providers can have multiple locations; NPPES lists the primary practice address.

Other providers at this practice address

Browse all →

Gregory Schenk Urology Physician · Leesburg, VA NPI 1649264185 John Pahira Urology Physician · Leesburg, VA NPI 1780672758 Loudoun Medical Group, PC Urology Physician · Leesburg, VA NPI 1710001102 Chuck Pruna Urology Physician · Leesburg, VA NPI 1407049265 Christine Tran Urology Physician · Leesburg, VA NPI 1235469206 Nathan Roberts Urology Physician · Lansdowne, VA NPI 1942526165 Kyle Lester Urology Physician · Leesburg, VA NPI 1225441660 Jennifer Mendrysa Family Nurse Practitioner · Leesburg, VA NPI 1982076899

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2024-01-10.