Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Gregory S Willis, M.D.

Radiation Oncology Physician in Tualatin, OR · enumerated 2005.

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

National Provider Identifier

1417941600

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Registry record

Entity type Individual (Type 1)

Name Gregory S Willis

Credential M.D.

Sex Male

Practice address 6489 Sw Borland Rd, Tualatin, OR, 97062

Phone (503) 692-4843

Fax (503) 692-6543

Enumeration date Sep 2, 2005

Last updated in NPPES Jul 31, 2025

Taxonomy & licenses

2085R0001X Radiation Oncology Physician Allopathic & Osteopathic Physicians · License MD2016-0015 (NM) Secondary

2471R0002X Radiation Therapy Radiologic Technologist Technologists, Technicians & Other Technical Service Providers · License MD28019 (OR) Secondary

2085R0001X Radiation Oncology Physician Allopathic & Osteopathic Physicians · License MD28019 (OR) 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
140838	Other	OR	MEDICARE PTAN
033138015	Other	OR	REGENCE BCBS

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 Gregory Willis?

The National Provider Identifier (NPI) for Gregory Willis is 1417941600, a Type 1 (individual) record in the CMS NPPES registry.

Where does Gregory Willis practice?

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

Other providers at this practice address

Browse all →

Meridian Park Radiation Oncolog Center, Inc Radiation Oncology Clinic/Center · Tualatin, OR NPI 1114019684 Meridian Park Radiation Oncology Center, Inc. Radiation Oncology Clinic/Center · Tualatin, OR NPI 1538330899 Meridian Park Oncology LLC Radiation Oncology Physician · Tualatin, OR NPI 1467996645

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2025-07-31.