John Charles Gustafson, M.D.
Obstetrics & Gynecology Physician · Ventura, CA
John Charles Gustafson, M.D. is an obstetrics & gynecology physician with a practice address in Ventura, California, and NPI 1003836016, issued on Jul 20, 2006. Check the license (California G36782, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- John Charles Gustafson
- Credential
- M.D.
- Primary taxonomy
- Obstetrics & Gynecology Physician 207V00000X
- License number
- G36782 CA
Self-reported in NPPES; status is on the state search - Practice location
- 2795 Loma Vista RD, Ventura, CA 93003
- Phone
- (805) 643-8695
- Enumerated
- Jul 20, 2006
- Record last updated
- Jul 9, 2007 (not updated in 19 years: call before relying on the address or phone)
- Fax
- (805) 643-2087
- Medicaid IDs
- RHM08608F CA
ZZZ82842Z CA
RHM08609F CA
RHM18553H CA - Medicare enrollment
- Enrolled (PECOS I20050520000481); accepts Medicare assignment
- Medical or professional school
- University Of Rochester School Of Medicine And Dentistry, 1977
- Entity
- Type 1 · individual
8 nearest obstetrics & gynecology physician records → All 5,088 in California → Look up another NPI →
Also registered at 2795 Loma Vista RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Anne Chezar-Garnett, R.N., C.N.M.Advanced Practice Midwife1841547122
- Jill Hall, M.D.Gynecology Physician1265607204
- Richard Reisman, MDObstetrics & Gynecology Physician1457367815
Verify John Charles Gustafson in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G36782Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
3.1 times the Medicare Part D claims of the average obstetrics & gynecology physician in 2024
516 Medicare Part D claims for 150 beneficiaries, against an average of 165 among the 28,733 providers of this specialty who prescribed in Part D. Brand-name drugs were 12% of claims.
Most prescribed
- Estradiol132 claims
- Progesterone43 claims
- Estradiol (Twice Weekly)36 claims
- Clotrimazole-Betamethasone22 claims
- Estradiol-Norethindrone Acetat17 claims
- Valacyclovir17 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.
Industry payments in 2024: $53.82
3 payments; by number, the most common kind was food and beverage; the largest payer was Bayer Healthcare Pharmaceuticals Inc. The 21,429 providers of this specialty with any payment received $1,030.61 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Community Memorial Health SystemVentura, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
John Charles Gustafson among 5,088 obstetrics & gynecology physician records in California
John Charles Gustafson, M.D. is one of 5,088 obstetrics & gynecology physician records with a practice address in California. 74% 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 5% of them.
- NPI issued2006 · 5% of these records are older, 52% newer
- In a Medicare fileYes · 74% of these records are
- In the CMS Doctors and Clinicians fileYes · 53% of these records are
- Graduated1977 · median 2004 among the 2,700 with a school on file
- Record last updated2007 · 64% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207V00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Obstetrics & Gynecology Physician providers in California
There are 5,088 obstetrics & gynecology physician records in California.
All 5,088 in California → Every provider in Ventura → Obstetrics & Gynecology Physician nationwide →
The 8 obstetrics & gynecology physician records with the nearest ZIP codes
- Lois Barnes, M.D.Ventura, CA 930031134233521
- Terry Cole, M.D.Ventura, CA 930031992748651
- Steven Coyle, MDVentura, CA 930031548276900
- Patrick Diesfeld, M.D.Ventura, CA 930031568576080
- Katherine Edwards, M.D.Ventura, CA 930031972635498
- Olivia Farfan-Gonzalez, M.D.Ventura, CA 930031720014376
- Jeffrey Martin, M.D.Ventura, CA 930031568490803
- Srisawai Pattamakom, M.D.Ventura, CA 930031114031648
Common questions
What is John Charles Gustafson, M.D.'s NPI number?
John Charles Gustafson, M.D.'s National Provider Identifier (NPI) is 1003836016, issued on Jul 20, 2006. An NPI identifies a provider in billing; it is not a license.
Where is John Charles Gustafson, M.D. located?
The NPPES record lists a practice address at 2795 Loma Vista RD, Ventura, CA, 93003. Phone: (805) 643-8695. Providers update this record themselves, so call before visiting.
How can I verify John Charles Gustafson, M.D.'s license?
NPPES lists California license number G36782, 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 John Charles Gustafson, M.D. prescribe under Medicare Part D?
In 2024, John Charles Gustafson, M.D. had 516 Medicare Part D claims for 150 beneficiaries; the average among obstetrics & gynecology physician prescribers was 165. 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.