Stephen Yoon, M.D.
Internal Medicine Physician · Fullerton, CA
Stephen Yoon, M.D. is an internal medicine physician with a practice address in Fullerton, California, and NPI 1851327100, issued on Jun 25, 2006. Check the license (California A71645, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Stephen Yoon
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A71645 CA
Self-reported in NPPES; status is on the state search - Practice location
- 101 E Valencia Mesa Dr, Fullerton, CA 92835
- Phone
- (714) 992-3000
- Enumerated
- Jun 25, 2006
- Record last updated
- May 13, 2015 (not updated in 11 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20071107000806); accepts Medicare assignment
- Medical or professional school
- Rutgers New Jersey Medical School, 1998
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 101 E Valencia Mesa Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Daniel Abbott, MDEmergency Medicine Physician1518907864
- Nelson Aguinaga, RN, FNPFamily Nurse Practitioner1043909609
- Jonathon Ahn, MDAnesthesiology Physician1053803882
- Sora Ahn, RNCritical Care Medicine Registered Nurse1730026493
- Sherry Ansari, DPTPhysical Medicine & Rehabilitation Physician1467972992
- Tandeep Bains, PHARM.D.Pharmacist1568958114
Verify Stephen Yoon in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A71645Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
84% fewer Medicare Part D claims than the average internal medicine physician in 2024
502 Medicare Part D claims for 186 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. 18 claims were for opioids.
Most prescribed
- Amoxicillin-Clavulanate Potass43 claims
- Furosemide29 claims
- Pantoprazole Sodium29 claims
- Atorvastatin Calcium27 claims
- Prednisone21 claims
- Clopidogrel19 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: $144.59
6 payments; by number, the most common kind was food and beverage; the largest payer was Pfizer Inc. The 50,334 providers of this specialty with any payment received $1,303.06 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
- Providence Medical FoundationFullerton, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Stephen Yoon among 17,696 internal medicine physician records in California
Stephen Yoon, M.D. 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 2006, is newer than 5% of them.
- NPI issued2006 · 5% of these records are older, 56% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated1998 · median 2004 among the 11,065 with a school on file
- Record last updated2015 · 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).
44 internal medicine physician records list a practice address in Fullerton
They are 44 of the 5,437 NPPES records with a practice address in Fullerton, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Fullerton → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Rajiv Bhavsar, M.D.Fullerton, CA 928351477550648
- Bradley Borsari, MDFullerton, CA 928351104826619
- Eugene BostonFullerton, CA 928351023019965
- Ruben Cabral, MDFullerton, CA 928351568458008
- Friedhelm Cordes, M.D.Fullerton, CA 928351588650931
- Robert Francis, M.D.Fullerton, CA 928351366439804
- Leo Garcia, M.D.Fullerton, CA 928351831185792
- Pius Kim, M.D.Fullerton, CA 928351003863317
Common questions
What is Stephen Yoon, M.D.'s NPI number?
Stephen Yoon, M.D.'s National Provider Identifier (NPI) is 1851327100, issued on Jun 25, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Stephen Yoon, M.D. located?
The NPPES record lists a practice address at 101 E Valencia Mesa Dr, Fullerton, CA, 92835. Phone: (714) 992-3000. Providers update this record themselves, so call before visiting.
How can I verify Stephen Yoon, M.D.'s license?
NPPES lists California license number A71645, 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 Stephen Yoon, M.D. prescribe under Medicare Part D?
In 2024, Stephen Yoon, M.D. had 502 Medicare Part D claims for 186 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.