Quick answers
- Which hospitals does John Leong work at?
- Medicare's official clinician data lists John Leong at 1 hospital: Kaiser Foundation Hospital Fontana/Ontario. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does John Leong see patients?
- Medicare's clinician data lists 1 practice location in Fontana, CA. Call before your visit to confirm the address.
- What is John Leong's specialty?
- Medicare lists Geriatric Medicine as the primary specialty.
- Does John Leong accept Medicare assignment?
- Yes. Medicare's clinician data says John Leong 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 John Leong offer telehealth?
- Medicare's clinician data says John Leong offers telehealth services. Ask the office which visits can be done by video or phone.
- What is the phone number for John Leong?
- (909) 427-5000, as listed in official Medicare / NPI Registry data.
- What is John Leong's NPI number?
- 1851896773. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where John Leong works
Medicare's Facility Affiliation Data lists John Leong at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Kaiser Foundation Hospital Fontana/OntarioFontana, CA · Acute Care Hospital · CCN 050140
Practice locations
Addresses where John Leong is enrolled with Medicare (CMS data updated 2026-10-02).
- 9961 Sierra AveFontana, CA 92335 (909) 427‑5000
Group practices
Medicare enrollment lists John Leong as a member of this group (CMS data updated 2026-10-02).
- Southern California Permanente Medical Group11,293 clinicians in the group
Specialties
- Geriatric Medicineprimary
Other geriatricians in Fontana
Clinicians with the same Medicare primary specialty in Fontana, CA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 2018 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1851896773 |
| 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