Quick answers
- Which hospitals does Mark W. Li work at?
- Medicare's official clinician data lists Mark W. Li at 1 hospital: Whittier Hospital Medical Center. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Mark W. Li see patients?
- Medicare's clinician data lists 2 practice locations, including Hacienda Heights, CA and Hacienda Hts, CA. Call before your visit to confirm the address.
- What is Mark W. Li's specialty?
- Medicare lists Gastroenterology as the primary specialty, and also Internal Medicine.
- Does Mark W. Li accept Medicare assignment?
- Yes. Medicare's clinician data says Mark W. Li accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
- What is the phone number for Mark W. Li?
- (626) 330-6003, as listed in official Medicare / NPI Registry data.
- What is Mark W. Li's NPI number?
- 1356375059. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Mark W. Li works
Medicare's Facility Affiliation Data lists Mark W. Li at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Whittier Hospital Medical CenterWhittier, CA · Acute Care Hospital · CCN 050735
Practice locations
Addresses where Mark W. Li is enrolled with Medicare (CMS data updated 2026-10-02).
- 2440 S Hacienda Blvd, Suite 105Hacienda Heights, CA 91745 (626) 330‑6003
- 2440 S Hacienda Blvd, Suite 105Hacienda Hts, CA 91745
Specialties
- Gastroenterologyprimary
- Internal Medicinealso
Other gastroenterologists in California
Clinicians with the same Medicare primary specialty in California — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Illinois College Of Med (chi/peor/rock/chm-Urb) |
| Graduation year | 1978 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1356375059 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians