Mon-Ta Tsai, M.D.
Internal Medicine Physician · Mission Viejo, CA
Mon-Ta Tsai, M.D. is an internal medicine physician with a practice address in Mission Viejo, California, and NPI 1427019231, issued on Mar 31, 2006. Check the license (California A65382, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Mon-Ta Tsai
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A65382 CA
Self-reported in NPPES; status is on the state search - Practice location
- 25982 Pala, Mission Viejo, CA 92691
- Phone
- (949) 588-0051
- Enumerated
- Mar 31, 2006
- Record last updated
- Jul 13, 2026
- Fax
- (949) 588-0052
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 25982 Pala
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Mon-Ta Tsai in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A65382Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
41% more Medicare Part D claims than the average internal medicine physician in 2024
4,469 Medicare Part D claims for 352 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. 37 claims were for opioids.
Most prescribed
- Losartan Potassium366 claims
- Amlodipine Besylate323 claims
- Rosuvastatin Calcium318 claims
- Atorvastatin Calcium269 claims
- Metformin Hcl165 claims
- Tamsulosin Hcl134 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: $175.43
3 payments; by number, the most common kind was food and beverage; the largest payer was Amgen 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.
Mon-Ta Tsai among 17,696 internal medicine physician records in California
Mon-Ta Tsai, 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 fileNo · 63% of these records are
- Record last updated2026 · 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).
58 internal medicine physician records list a practice address in Mission Viejo
They are 58 of the 2,156 NPPES records with a practice address in Mission Viejo, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Mission Viejo → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Bahman Badie, M.D.Mission Viejo, CA 926911396721916
- Sherif El Sokkary, M.D.Mission Viejo, CA 926911710964432
- Dennis Haghighat, M.D.Mission Viejo, CA 926911568449171
- Mark Hauptman, M.D.Mission Viejo, CA 926911801873427
- Raymond Kwa, M.D.Mission Viejo, CA 926911609853092
- Murray Margolis, M.D.Mission Viejo, CA 926911457338857
- Vy Nguyen, M.D.Mission Viejo, CA 926911881671154
- Nader Noorian, M.D.Mission Viejo, CA 926911861479057
Common questions
What is Mon-Ta Tsai, M.D.'s NPI number?
Mon-Ta Tsai, M.D.'s National Provider Identifier (NPI) is 1427019231, issued on Mar 31, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Mon-Ta Tsai, M.D. located?
The NPPES record lists a practice address at 25982 Pala, Mission Viejo, CA, 92691. Phone: (949) 588-0051. Providers update this record themselves, so call before visiting.
How can I verify Mon-Ta Tsai, M.D.'s license?
NPPES lists California license number A65382, 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 Mon-Ta Tsai, M.D. prescribe under Medicare Part D?
In 2024, Mon-Ta Tsai, M.D. had 4,469 Medicare Part D claims for 352 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.