Gregory S. Willis, DO

NPI 1184605677ActiveIndividual· Obstetrics & Gynecology, Gynecologic Oncology· York, PA

Obstetrics & Gynecology, Gynecologic Oncology (DO) in York, Pennsylvania, trained at University of North Texas Hsc, College of Osteopathic Med (class of 1994). Their prescriptions cost Medicare Part D more than their services did: $341,695 for 234 claims, against $56,980 paid for services in 2024. Eisai Inc. reported $107.10 in payments in 2025, mostly food and beverage.

Overview

NPI	1184605677
Status	Active
Entity type	Individual
Credential	DO
Sole proprietor	No
NPI issued	Nov 10, 2005
Last updated in NPPES	Jan 23, 2021
Certified by provider	Jan 23, 2021

Specialties and licenses

Taxonomy	Code	License	State
Obstetrics & Gynecology, Gynecologic Oncology Primary	207VX0201X	OS009400L	PA

About license numbers in NPPES

Exclusion screening

List	Result	Details
HHS-OIG LEIE · Nov 10, 2026	No match	Checked by NPI and by name + state
North Carolina Medicaid · Nov 11, 2026	No match	—
New York OMIG · Nov 11, 2026	No match	—
Ohio Medicaid · Nov 11, 2026	No match	—
Pennsylvania Medicheck · Nov 11, 2026	No match	—
Washington HCA · Nov 11, 2026	No match	—

Official OIG search · How matching works ·Bulk check a roster

Medicare

Enrollment (PECOS)	Enrolled Practitioner - Gynecological Oncology (PA)
Accepts assignment	Yes (participating)

Medicare services in 2024

Medicare patients	127
Services billed	404 across 43 procedure codes
Paid by Medicare	$56,980

Part D prescriptions in 2024

Prescriptions (claims)	234 · 279 30-day fills
Patients	77
Total drug cost	$341,695
Generic share	85% of claims

Medicare sources and data years

Education and affiliations

Medical school	University of North Texas Hsc, College of Osteopathic Med
Graduation year	1994
Medicare specialty	Gynecological Oncology
Secondary specialties	Obstetrics/Gynecology