Quick answers
- Which hospitals does Mark Williams work at?
- Medicare's official clinician data lists Mark Williams at 3 hospitals: Keck Hospital of USC, Los Angeles General Medical Center and USC Verdugo Hills Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Mark Williams see patients?
- Medicare's clinician data lists 9 practice locations, including Los Angeles, CA and Arcadia, CA. Call before your visit to confirm the address.
- What is Mark Williams's specialty?
- Medicare lists Nephrology as the primary specialty, and also Internal Medicine.
- Does Mark Williams accept Medicare assignment?
- Yes. Medicare's clinician data says Mark Williams 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.
- Does Mark Williams offer telehealth?
- Medicare's clinician data says Mark Williams offers telehealth services. Ask the office which visits can be done by video or phone.
- What is the phone number for Mark Williams?
- (323) 865-3000, as listed in official Medicare / NPI Registry data.
- What is Mark Williams's NPI number?
- 1184653891. 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 Williams works
Medicare's Facility Affiliation Data lists Mark Williams at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Keck Hospital of USCLos Angeles, CA · Acute Care Hospital · CCN 050696
- Los Angeles General Medical CenterLos Angeles, CA · Acute Care Hospital · CCN 050373
- USC Verdugo Hills HospitalGlendale, CA · Acute Care Hospital · CCN 050124
Practice locations
Addresses where Mark Williams is enrolled with Medicare (CMS data updated 2026-10-02). The first 5 of 9; the Medicare profile lists all.
- 1441 Eastlake AveLos Angeles, CA 90089 (323) 865‑3000
- 1500 San Pablo StLos Angeles, CA 90033
- 1516 San Pablo StLos Angeles, CA 90033 (800) 872‑2273
- 1516 San Pablo St, Suite L3100Los Angeles, CA 90033 (800) 872‑2273
- 1520 San Pablo StLos Angeles, CA 90033 (800) 872‑2273
Group practices
Medicare enrollment lists Mark Williams as a member of these groups (CMS data updated 2026-10-02).
- USC Care Medical Group Inc1,380 clinicians in the group
- USC Care Medical Non-Contracted LLC18 clinicians in the group
Specialties
- Nephrologyprimary
- Internal Medicinealso
Other nephrologists in Los Angeles
Clinicians with the same Medicare primary specialty in Los Angeles, CA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Indiana University School Of Medicine |
| Graduation year | 1977 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1184653891 |
| 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