Robert A. Williams, M.D.
Family Medicine Physician · Ventura, CA
Robert A. Williams, M.D. is a family medicine physician with a practice address in Ventura, California, and NPI 1245400951, issued on Mar 10, 2008. Check the license (California A99934, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Robert A. Williams
- Credential
- M.D.
- Primary taxonomy
- Family Medicine Physician 207Q00000X
- License number
- A99934 CA
Self-reported in NPPES; status is on the state search - Practice location
- 3291 Loma Vista RD, Ventura, CA 93003
- Phone
- (805) 652-6656
- Enumerated
- Mar 10, 2008
- Record last updated
- Sep 17, 2020 (not updated in 6 years: call before relying on the address or phone)
- Entity
- Type 1 · individual
8 nearest family medicine physician records → All 17,133 in California → Look up another NPI →
Also registered at 3291 Loma Vista RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Robert A. Williams in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A99934Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
69% fewer Medicare Part D claims than the average family medicine physician in 2024
1,090 Medicare Part D claims for 82 beneficiaries, against an average of 3,544 among the 117,163 providers of this specialty who prescribed in Part D. Brand-name drugs were 14% of claims.
Most prescribed
- Levothyroxine Sodium71 claims
- Atorvastatin Calcium59 claims
- Levetiracetam45 claims
- Lisinopril40 claims
- Gabapentin38 claims
- Metoprolol Tartrate38 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 A. Williams among 17,133 family medicine physician records in California
Robert A. Williams, M.D. is one of 17,133 family medicine physician records with a practice address in California. 81% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2008, is newer than 53% of them.
- NPI issued2008 · 53% of these records are older, 42% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileNo · 62% of these records are
- Record last updated2020 · 58% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207Q00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
234 family medicine physician records list a practice address in Ventura
They are 234 of the 4,435 NPPES records with a practice address in Ventura, and 17,133 family medicine physician records in California.
All 17,133 in California → Every provider in Ventura → Family Medicine Physician nationwide →
The 8 family medicine physician records with the nearest ZIP codes
- Charles Adams, M.D.Ventura, CA 930031811925225
- Veronica Butler, M.D.Ventura, CA 930031063472736
- Eric Chun, M.D.Ventura, CA 930031699702381
- Michelle Daucett, D.O.Ventura, CA 930031003873035
- Derrick Dcosta, M.D.Ventura, CA 930031487699005
- James Hermann, M.D.Ventura, CA 930031861442899
- Theodore Hole, M.D.Ventura, CA 930031104873611
- Andrew Kerr, M.D.Ventura, CA 930031487695078
Common questions
What is Robert A. Williams, M.D.'s NPI number?
Robert A. Williams, M.D.'s National Provider Identifier (NPI) is 1245400951, issued on Mar 10, 2008. An NPI identifies a provider in billing; it is not a license.
Where is Robert A. Williams, M.D. located?
The NPPES record lists a practice address at 3291 Loma Vista RD, Ventura, CA, 93003. Phone: (805) 652-6656. Providers update this record themselves, so call before visiting.
How can I verify Robert A. Williams, M.D.'s license?
NPPES lists California license number A99934, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Robert A. Williams, M.D. prescribe under Medicare Part D?
In 2024, Robert A. Williams, M.D. had 1,090 Medicare Part D claims for 82 beneficiaries; the average among family medicine physician prescribers was 3,544. 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.