NPPES file of Aug 9, 2026

Chun Ouyang, M.D., PH.D.

Internal Medicine Physician · Walnut Creek, CA

Chun Ouyang, M.D., PH.D. is an internal medicine physician with a practice address in Walnut Creek, California, and NPI 1336115328, issued on Feb 28, 2006. Check the license on the Medical Board of California; the Medicare figures below come from public CMS files.

Record from CMS NPPES, file of Aug 9, 2026 · Medicare files 2024 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1336115328
Name
Chun Ouyang
Credential
M.D., PH.D.
Primary taxonomy
Internal Medicine Physician 207R00000X
License number
217077 MA
Self-reported in NPPES; status is on the state search
Practice location
1425 S Main St, Walnut Creek, CA 94596
Phone
(925) 295-4020
Enumerated
Feb 28, 2006
Record last updated
Dec 13, 2021 (not updated in 5 years: call before relying on the address or phone)
Medicare enrollment
Enrolled (PECOS I20071114000594); accepts Medicare assignment
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). Enrollment, assignment, school and telehealth: CMS Doctors and Clinicians file, Aug 2026. A record is not a license: verify it with the state board.
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Also registered at 1425 S Main St

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Eric AaserudeEmergency Medicine Physician1811491194
  2. Derek Abbassi, MDObstetrics & Gynecology Physician1841364155
  3. Peter Ackerman, MDEmergency Medicine Physician1427435023
  4. Aaron Mark Acosta, DOEmergency Medicine Physician1538789987
  5. Basil Adad, MDOtolaryngology Physician1487732574
  6. Derek Ailes, M.D.Emergency Medical Services (Emergency Medicine) Physician1992001804

Verify Chun Ouyang in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersMedical Board of CaliforniaCheck the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Open the California license search

PlainDoctor does not match the HHS-OIG exclusion list to individual records: most entries carry no NPI. Search the OIG exclusion list by name.

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69% fewer Medicare Part D claims than the average internal medicine physician in 2024

983 Medicare Part D claims for 477 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 13% of claims. 25 claims were for opioids.

  1. Chun Ouyang983
  2. Specialty average3,176

Most prescribed

  1. Gavilyte-C335 claims
  2. Cholestyramine48 claims
  3. Omeprazole47 claims
  4. Mesalamine41 claims
  5. Entecavir37 claims
  6. Pantoprazole Sodium34 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: $21.57

1 payment: food and beverage; the largest payer was CapsoVision, 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.

  1. Chun Ouyang$21.57
  2. Specialty average$1,303.06

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

  1. Permanente Medical Group IncWalnut Creek, CA

Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).

Chun Ouyang among 17,696 internal medicine physician records in California

Chun Ouyang, M.D., PH.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
  • Graduated1992 · median 2004 among the 11,065 with a school on file
  • Record last updated2021 · 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).

183 internal medicine physician records list a practice address in Walnut Creek

They are 183 of the 6,170 NPPES records with a practice address in Walnut Creek, and 17,696 internal medicine physician records in California.

The 8 internal medicine physician records with the nearest ZIP codes

  1. Anthony Arroyo, MDWalnut Creek, CA 945961376621458
  2. Sheila Bhatia, MDWalnut Creek, CA 945961225135379
  3. Amrita Dhaliwal, MDWalnut Creek, CA 945961164500740
  4. Nellia Karakozova, MDWalnut Creek, CA 945961659459154
  5. Joseph Long, MDWalnut Creek, CA 945961225116379
  6. Roxanne McDaniel, MDWalnut Creek, CA 945961457439937
  7. Huu Nguyen, D.O.Walnut Creek, CA 945961811966492
  8. Jeff Ortiz, MDWalnut Creek, CA 945961891873964

Common questions

What is Chun Ouyang, M.D., PH.D.'s NPI number?

Chun Ouyang, M.D., PH.D.'s National Provider Identifier (NPI) is 1336115328, issued on Feb 28, 2006. An NPI identifies a provider in billing; it is not a license.

Where is Chun Ouyang, M.D., PH.D. located?

The NPPES record lists a practice address at 1425 S Main St, Walnut Creek, CA, 94596. Phone: (925) 295-4020. Providers update this record themselves, so call before visiting.

How can I verify Chun Ouyang, M.D., PH.D.'s license?

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 Chun Ouyang, M.D., PH.D. prescribe under Medicare Part D?

In 2024, Chun Ouyang, M.D., PH.D. had 983 Medicare Part D claims for 477 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.