Gregory H. Johnson, MD
Gastroenterology Physician · Thousand Oaks, CA
Gregory H. Johnson, MD is a gastroenterology physician with a practice address in Thousand Oaks, California, and NPI 1952463762, issued on Dec 15, 2006. Check the license (California G25258, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Gregory H. Johnson
- Credential
- MD
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License number
- G25258 CA
Self-reported in NPPES; status is on the state search - Practice location
- 227 W Janss RD, Thousand Oaks, CA 91360
- Phone
- (805) 497-9597
- Enumerated
- Dec 15, 2006
- Record last updated
- Jul 8, 2007 (not updated in 19 years: call before relying on the address or phone)
- Entity
- Type 1 · individual
8 nearest gastroenterology physician records → All 2,140 in California → Look up another NPI →
Also registered at 227 W Janss RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Gregory H. Johnson in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G25258Check 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
17 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 0% 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.
Gregory H. Johnson among 2,140 gastroenterology physician records in California
Gregory H. Johnson, MD is one of 2,140 gastroenterology physician records with a practice address in California. 83% 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, 48% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileNo · 72% of these records are
- Record last updated2007 · 60% 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 California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Gastroenterology Physician providers in California
There are 2,140 gastroenterology physician records in California.
All 2,140 in California → Every provider in Thousand Oaks → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Michael Albertson, M.D.Thousand Oaks, CA 913601114035128
- Shahram Daneshgar, MDThousand Oaks, CA 913601730191875
- Kumar Desai, M.D.Thousand Oaks, CA 913601841495728
- Bonaventure Eng, MDThousand Oaks, CA 913601538366489
- Steven Kind, MDThousand Oaks, CA 913601811005044
- Paul Sanders, MDThousand Oaks, CA 913601629044748
- Gilbert Simoni, M.D., FACGThousand Oaks, CA 913601316922958
- Hector Caballero, MDWestlake Village, CA 913611174515662
Common questions
What is Gregory H. Johnson, MD's NPI number?
Gregory H. Johnson, MD's National Provider Identifier (NPI) is 1952463762, issued on Dec 15, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Gregory H. Johnson, MD located?
The NPPES record lists a practice address at 227 W Janss RD, Thousand Oaks, CA, 91360. Phone: (805) 497-9597. Providers update this record themselves, so call before visiting.
How can I verify Gregory H. Johnson, MD's license?
NPPES lists California license number G25258, 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 Gregory H. Johnson, MD prescribe under Medicare Part D?
In 2024, Gregory H. Johnson, MD had 17 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.