Robert C. Williams, M.D.
Gastroenterology Physician · Westminster, CO
Robert C. Williams, M.D. is a gastroenterology physician with a practice address in Westminster, Colorado, and NPI 1922042571, issued on Jun 15, 2006. Check the license (Colorado 17931, as entered in NPPES) on the Colorado Medical Board; the Medicare figures below come from public CMS files.
- Name
- Robert C. Williams
- Credential
- M.D.
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License number
- 17931 CO
Self-reported in NPPES; status is on the state search - Practice location
- 8406 Clay St, Westminster, CO 80031
- Phone
- (720) 443-8461
- Enumerated
- Jun 15, 2006
- Record last updated
- Dec 22, 2016 (not updated in 10 years: call before relying on the address or phone)
- Fax
- (303) 427-4291
- Medicaid ID
- 000018530 AL
- Entity
- Type 1 · individual
8 nearest gastroenterology physician records → All 334 in Colorado → Look up another NPI →
Also registered at 8406 Clay St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Jerry Cupps, MDFamily Medicine Physician1356473474
- Claudia Morales, PA-CPhysician Assistant1497295265
- Peter Nicholson, MDInternal Medicine Physician1629103585
Verify Robert C. Williams in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersColorado Medical Board
Search for license 17931Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
98% fewer Medicare Part D claims than the average gastroenterology physician in 2024
20 Medicare Part D claims, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D. Brand-name drugs were 70% of claims.
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Robert C. Williams among 334 gastroenterology physician records in Colorado
Robert C. Williams, M.D. is one of 334 gastroenterology physician records with a practice address in Colorado. 84% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 7% of them.
- NPI issued2006 · 7% of these records are older, 53% newer
- In a Medicare fileYes · 84% of these records are
- In the CMS Doctors and Clinicians fileNo · 77% of these records are
- Record last updated2016 · 49% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RG0100X and a Colorado practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Gastroenterology Physician providers in Colorado
There are 334 gastroenterology physician records in Colorado.
All 334 in Colorado → Every provider in Westminster → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Carl Dahl, M.D.Wheat Ridge, CO 800331023052891
- Michael Firth, M.D.Wheat Ridge, CO 800331386688893
- Korina Bersentes, M.D.Superior, CO 800271447282603
- Scott Hallgren, D.O., F.A.C.P.Louisville, CO 800271205929841
- Colin Leffert, DOLouisville, CO 800271881127140
- John Mengshol, MDLouisville, CO 800271932255544
- Erica Boettcher, MDLafayette, CO 800261609038454
- Joseph Cassara, M.D.Lafayette, CO 800261275755290
Common questions
What is Robert C. Williams, M.D.'s NPI number?
Robert C. Williams, M.D.'s National Provider Identifier (NPI) is 1922042571, issued on Jun 15, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Robert C. Williams, M.D. located?
The NPPES record lists a practice address at 8406 Clay St, Westminster, CO, 80031. Phone: (720) 443-8461. Providers update this record themselves, so call before visiting.
How can I verify Robert C. Williams, M.D.'s license?
NPPES lists Colorado license number 17931, as entered by the provider. Search the Colorado Medical Board at https://dpo.colorado.gov/Medical. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Robert C. Williams, M.D. prescribe under Medicare Part D?
In 2024, Robert C. Williams, M.D. had 20 Medicare Part D claims; the average among gastroenterology physician prescribers was 811. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.