Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
William J O'Brien, MD
Surgery Physician in Aurora, IL · enumerated 2006.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1831101955
See something wrong? Report a correction
Registry record
Entity type Individual (Type 1)
Name William J O'Brien
Credential MD
Sex Male
Practice address 1221 N Highland Ave, Aurora, IL, 60506
Phone (630) 859-8700
Enumeration date Aug 13, 2006
Last updated in NPPES Nov 18, 2021
Taxonomy & licenses
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 |
|---|---|---|---|
| 036092894 | Medicaid | IL | - |
| 04515143 | Other | IL | BLUECROSS BLUESHIELD |
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.
Frequently asked questions
Is NPI 1831101955 active?
Yes, as of the latest NPPES snapshot, NPI 1831101955 is active (record last updated 2021-11-18).
How do I verify William O'Brien's NPI record?
Cross-check NPI 1831101955 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.
Other providers at this practice address
Browse all → James Studlo Diagnostic Radiology Physician · Aurora, IL NPI 1407857105 Katherine Kouvelis Surgery Physician · Aurora, IL NPI 1861493165 Thomas White Orthopaedic Surgery Physician · Aurora, IL NPI 1104813435 John Tauscher Diagnostic Radiology Physician · Aurora, IL NPI 1902894231 Jill Austin Podiatrist · Aurora, IL NPI 1730164047 Rachel Bullar Physical Therapist · Aurora, IL NPI 1023095650 Shruti Parekh Physician Assistant · Aurora, IL NPI 1598745275 Steven Rabin Orthopaedic Surgery Physician · Aurora, IL NPI 1487628525
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2021-11-18.