Jonathan S. Warnelo, D.O.
Internal Medicine Physician · Garden Grove, CA
Jonathan S. Warnelo, D.O. is an internal medicine physician with a practice address in Garden Grove, California, and NPI 1467980854, issued on May 30, 2017. Check the license (California 20A16595, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Jonathan S. Warnelo
- Credential
- D.O.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 20A16595 CA
Self-reported in NPPES; status is on the state search - Practice location
- 12665 Garden Grove Blvd, Garden Grove, CA 92843
- Phone
- (714) 537-7800
- Enumerated
- May 30, 2017
- Record last updated
- Sep 20, 2019 (not updated in 7 years: call before relying on the address or phone)
- Fax
- (714) 537-7633
- Medicare enrollment
- Enrolled (PECOS I20190819002484); accepts Medicare assignment
- Medical or professional school
- Lake Erie College Of Osteopathic Medicine, Erie, 2016
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 12665 Garden Grove Blvd
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Mumtaz Ali, M.DSpecialist1700849049
- James Boyce, M.D.Ophthalmology Physician1457351652
- Allen Chou, MDGeriatric Medicine (Internal Medicine) Physician1215919915
- Douglas Clark, M.D.Internal Medicine Physician1780688572
- Naveen Dhar, M.D.Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician1871604116
- Usha Dhar, M.D.Family Medicine Physician1699886846
Verify Jonathan S. Warnelo in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A16595Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
87% fewer Medicare Part D claims than the average internal medicine physician in 2024
415 Medicare Part D claims for 119 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 9% of claims. 17 claims were for opioids.
Most prescribed
- Amlodipine Besylate28 claims
- Pantoprazole Sodium23 claims
- Olanzapine22 claims
- Losartan Potassium20 claims
- Levofloxacin18 claims
- Carvedilol15 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.
Bills Medicare through one group practice
- Pathway Medical Group IncWestminster, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Jonathan S. Warnelo among 17,696 internal medicine physician records in California
Jonathan S. Warnelo, D.O. is one of 17,696 internal medicine physician records with a practice address in California. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2017, is newer than 81% of them.
- NPI issued2017 · 81% of these records are older, 16% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2016 · median 2004 among the 11,065 with a school on file
- Record last updated2019 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
39 internal medicine physician records list a practice address in Garden Grove
They are 39 of the 4,572 NPPES records with a practice address in Garden Grove, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Garden Grove → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Douglas Clark, M.D.Garden Grove, CA 928431780688572
- Asaad Hakim, M.D.Garden Grove, CA 928431477504082
- Julie Hwynn, M.D.Garden Grove, CA 928431780682401
- Shireen Khalife, DOGarden Grove, CA 928431962922393
- Se-Young Lee, M.D.Garden Grove, CA 928431144336967
- Euil Lim, D.OGarden Grove, CA 928431770930828
- Philip Lynn, M.D.Garden Grove, CA 928431326044819
- Tuan Xuan Nguyen, MDGarden Grove, CA 928431679519821
Common questions
What is Jonathan S. Warnelo, D.O.'s NPI number?
Jonathan S. Warnelo, D.O.'s National Provider Identifier (NPI) is 1467980854, issued on May 30, 2017. An NPI identifies a provider in billing; it is not a license.
Where is Jonathan S. Warnelo, D.O. located?
The NPPES record lists a practice address at 12665 Garden Grove Blvd, Garden Grove, CA, 92843. Phone: (714) 537-7800. Providers update this record themselves, so call before visiting.
How can I verify Jonathan S. Warnelo, D.O.'s license?
NPPES lists California license number 20A16595, 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 Jonathan S. Warnelo, D.O. prescribe under Medicare Part D?
In 2024, Jonathan S. Warnelo, D.O. had 415 Medicare Part D claims for 119 beneficiaries; the average among internal medicine physician prescribers was 3,176. 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.