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Internal Medicine

Marcus S. Dempster, MD

Sees patients in Williamsville, NY · New York

Summary

Dr. Marcus S. Dempster, MD is an internal medicine doctor at 199 Park Club Ln, Williamsville, NY 14221. Accepts Medicare assignment. NPI 1881223519. Source: CMS National Downloadable File, updated October 2, 2026.

  • Specialty: Internal medicine doctor (Medicare lists Internal Medicine)
  • Address: 199 Park Club Ln, Williamsville, NY 14221 · Directions
  • Medicare: Accepts Medicare assignment
  • Group practice: Rpci Oncology, PC
  • Medical school: Wright State University Boonshoft School Of Medicine · graduated 2020 (6 years since medical school)
  • Gender (as listed): Male

From official Medicare data

This page shows what Medicare's official clinician data says about Marcus S. Dempster, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Marcus S. Dempster accept Medicare assignment?
Yes. Medicare's clinician data says Marcus S. Dempster accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
What is Marcus S. Dempster's NPI number?
1881223519. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Practice locations

Addresses where Marcus S. Dempster is enrolled with Medicare (CMS data updated October 2, 2026).

  • 199 Park Club LnWilliamsville, NY 14221

Group practices

Medicare enrollment lists Marcus S. Dempster as a member of this group (CMS data updated October 2, 2026).

  • Rpci Oncology, PC65 clinicians in the group

Specialties

Find other Internal Medicine doctors in New York →

Other internal medicine doctors in Williamsville

Clinicians with the same Medicare primary specialty in Williamsville, NY — not a recommendation.

All internal medicine doctors in Williamsville →

Other clinicians in Rpci Oncology, PC

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialMD
Medical schoolWright State University Boonshoft School Of Medicine
Graduation year2020 (6 years since medical school)
Gender (as listed)Male
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1881223519
CorrectionsReport an error or suggest an update →

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

  1. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  2. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  3. Medicare Care Compare — official Medicare tool to look up clinicians