Medical emergency?Emergency? Call 911. Nearest emergency roomsNearest ERs

Internal Medicine

Thomas J. Williamson, MD

Sees patients in Houston, TX · Texas

Summary

Thomas J. Williamson, MD (Internal Medicine) is enrolled with Medicare at 1 practice location in Houston, TX. NPI 1013003201. Medicare data says the clinician accepts Medicare assignment. Source: CMS National Downloadable File, updated 2026-10-02.

From official Medicare data

This page shows what Medicare's official clinician data says about Thomas J. Williamson, joined by NPI number (data updated 2026-10-02). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

At a glance

Internal MedicinePrimary specialty
YesAccepts Medicare assignment
29Years since medical school (graduated 1997)
Ohio State University College Of MedicineMedical school
MaleGender (as listed)
Kelsey-Seybold Medical Group, PLLCGroup practice

Quick answers

Where does Thomas J. Williamson see patients?
Medicare's clinician data lists 1 practice location in Houston, TX. Call before your visit to confirm the address.
What is Thomas J. Williamson's specialty?
Medicare lists Internal Medicine as the primary specialty.
Does Thomas J. Williamson accept Medicare assignment?
Yes. Medicare's clinician data says Thomas J. Williamson accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
What is the phone number for Thomas J. Williamson?
(713) 442-3222, as listed in official Medicare / NPI Registry data.
What is Thomas J. Williamson's NPI number?
1013003201. 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 Thomas J. Williamson is enrolled with Medicare (CMS data updated 2026-10-02).

Group practices

Medicare enrollment lists Thomas J. Williamson as a member of this group (CMS data updated 2026-10-02).

  • Kelsey-Seybold Medical Group, PLLC957 clinicians in the group

Specialties

Find other Internal Medicine doctors in Texas →

Other internal medicine doctors in Houston

Clinicians with the same Medicare primary specialty in Houston, TX — not a recommendation.

All internal medicine doctors in Houston →

Clinician information

CredentialMD
Medical schoolOhio State University College Of Medicine
Graduation year1997
Gender (as listed)Male
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1013003201
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 2026-10-02, retrieved 2026-10-29
  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