NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Ronald C Gregus, M.D.

Preventive Medicine/Occupational Environmental Medicine Physician in Aurora, IL · enumerated 2007.

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

National Provider Identifier

1205953684

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)
Name Ronald C Gregus
Credential M.D.
Sex Male
Practice address 4000 Ogden Ave, Aurora, IL, 60504
Phone (615) 778-4066
Enumeration date Mar 23, 2007
Last updated in NPPES Jul 8, 2007

Taxonomy & licenses

2083P0500X Preventive Medicine/Occupational Environmental Medicine Physician Allopathic & Osteopathic Physicians · License 036-083618 (IL) Primary
MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD 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

What is the NPI number for Ronald Gregus?
The National Provider Identifier (NPI) for Ronald Gregus is 1205953684, a Type 1 (individual) record in the CMS NPPES registry.
Where does Ronald Gregus practice?
The practice location on file with NPPES is in Aurora, IL. Providers can have multiple locations; NPPES lists the primary practice address.

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-07-08.