NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. Mark Chung-Hsun Tsai, M.D.

Internal Medicine Physician in Paramount, CA · enumerated 2005.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1225033111

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)
Name Dr. Mark Chung-Hsun Tsai
Credential M.D.
Sex Male
Practice address Paramount, CA, 90723
Phone (562) 634-6341
Fax (562) 634-8949
Enumeration date Jun 16, 2005
Last updated in NPPES Apr 3, 2017

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License A81875 (CA) Primary
MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier Type State Issuer
A81875 Other CA CALIFORNIA LICENSE

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

Where does Mark Tsai practice?
The practice location on file with NPPES is in Paramount, CA. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Mark Tsai?
The National Provider Identifier (NPI) for Mark Tsai is 1225033111, a Type 1 (individual) record in the CMS NPPES registry.

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2017-04-03.