Marc-Alan Iwahashi, M.D.,
Family Medicine Physician · Cupertino, CA
Marc-Alan Iwahashi, M.D., is a family medicine physician with a practice address in Cupertino, California, and NPI 1235123985, issued on Sep 8, 2005. Check the license (California G68531, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Marc-Alan Iwahashi
- Credential
- M.D.,
- Primary taxonomy
- Family Medicine Physician 207Q00000X
- License number
- G68531 CA
Self-reported in NPPES; status is on the state search - Practice location
- 20555 Prospect RD, Cupertino, CA 95014
- Phone
- (408) 253-5811
- Enumerated
- Sep 8, 2005
- Record last updated
- Jan 5, 2012 (not updated in 14 years: call before relying on the address or phone)
- Fax
- (408) 725-0583
- Medicaid ID
- 00G685310 CA
- Medicare enrollment
- Enrolled (PECOS I20110818000625); accepts Medicare assignment
- Medical or professional school
- University Of California, San Francisco School Of Medicine, 1987
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest family medicine physician records → All 17,133 in California → Look up another NPI →
Also registered at 20555 Prospect RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Aline ArredondoStudent in an Organized Health Care Education/Training Program1538051362
- Amanda CarnesStudent in an Organized Health Care Education/Training Program1649162462
- Ariana Cazares, BCBA, MSBehavior Analyst1568260909
- Adriana CisnerosBehavior Analyst1609673029
- Noah CrossBehavior Technician1023900479
- Dana Angela DimagmaliwStudent in an Organized Health Care Education/Training Program1417849340
Verify Marc-Alan Iwahashi in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G68531Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
11% fewer Medicare Part D claims than the average family medicine physician in 2024
3,154 Medicare Part D claims for 404 beneficiaries, against an average of 3,544 among the 117,163 providers of this specialty who prescribed in Part D. Brand-name drugs were 12% of claims.
Most prescribed
- Amlodipine Besylate240 claims
- Atorvastatin Calcium237 claims
- Levothyroxine Sodium176 claims
- Metformin Hcl151 claims
- Losartan Potassium147 claims
- Rosuvastatin Calcium135 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.
The practice group's MIPS final score for 2023 (Medicare payment program): 83.6 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $48.44
2 payments; by number, the most common kind was food and beverage; the largest payer was Exact Sciences Corporation. The 55,478 providers of this specialty with any payment received $902.55 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
- EL Camino Health Medical Network LLCMountain View, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Marc-Alan Iwahashi among 17,133 family medicine physician records in California
Marc-Alan Iwahashi, M.D., is one of 17,133 family medicine physician records with a practice address in California. 81% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2005, is newer than 0% of them.
- NPI issued2005 · 0% of these records are older, 94% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileYes · 62% of these records are
- Graduated1987 · median 2005 among the 10,652 with a school on file
- Record last updated2012 · 58% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207Q00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
10 family medicine physician records list a practice address in Cupertino
They are 10 of the 945 NPPES records with a practice address in Cupertino, and 17,133 family medicine physician records in California.
All 17,133 in California → Every provider in Cupertino → Family Medicine Physician nationwide →
The 8 family medicine physician records with the nearest ZIP codes
- Fernand Alvarez, M.D.Cupertino, CA 950141437167582
- Sara Bowling, M.D.Cupertino, CA 950141942576194
- Yung-Kuang Chen, MDCupertino, CA 950141619009404
- John Chiu, M.D.Cupertino, CA 950141184716136
- Melissa Lin, MDCupertino, CA 950141205903200
- Matthew Manighalam, MDCupertino, CA 950141871079640
- Manjul Patwardhan, MDCupertino, CA 950141659398360
- Hung-Kwong Wong, M.D.Cupertino, CA 950141669558821
Common questions
What is Marc-Alan Iwahashi, M.D.,'s NPI number?
Marc-Alan Iwahashi, M.D.,'s National Provider Identifier (NPI) is 1235123985, issued on Sep 8, 2005. An NPI identifies a provider in billing; it is not a license.
Where is Marc-Alan Iwahashi, M.D., located?
The NPPES record lists a practice address at 20555 Prospect RD, Cupertino, CA, 95014. Phone: (408) 253-5811. Providers update this record themselves, so call before visiting.
How can I verify Marc-Alan Iwahashi, M.D.,'s license?
NPPES lists California license number G68531, 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 Marc-Alan Iwahashi, M.D., prescribe under Medicare Part D?
In 2024, Marc-Alan Iwahashi, M.D., had 3,154 Medicare Part D claims for 404 beneficiaries; the average among family medicine physician prescribers was 3,544. Part D covers Medicare prescriptions only.
What is Marc-Alan Iwahashi, M.D.,'s MIPS final score?
The 2023 MIPS final score is 83.6 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
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.