Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

John Grady Williams, MD

Individual provider Diagnostic Radiology Physician · NPI 1902855281

John Grady Williams, MD practises Diagnostic Radiology in Austin, Texas. Graduated from Texas Tech University Health Science Center School of Medicine in 2001, 25 years ago. Practices with Singleton Associates PA, a 795-clinician group and accepts Medicare assignment. Licensed in Texas.

Years since qualifying
25
Trained at
Texas Tech University Health Science Center School of Medicine
Licensed in
TX
In the registry since
2006
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

12554 Riata Vista Cir
Austin, TX 78727-6431
Phone: (512) 795-5100
Fax: (512) 795-5122
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Diagnostic Radiology Physician (primary) Taxonomy 2085R0202X · Licence M6955 (TX)

Record details

NPI number1902855281
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedMay 6, 2006
Last updated in NPPESOctober 3, 2018

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyDIAGNOSTIC RADIOLOGY
Medical schoolTEXAS TECH UNIVERSITY HEALTH SCIENCE CENTER SCHOOL OF MEDICINE
Graduated 2001 (25 years in practice)
Group practice Singleton Associates Pa — 795 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 on file with Medicare

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients3,370
Services billed 16,325 a service is one billed item, such as a visit, a test or a procedure
Average patient age75

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $272 2 payments · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician. Those with a page here are linked.

Colleagues at Singleton Associates PA

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 795 clinicians in the practice; 12 are shown here.

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