Quick answers
- Where does James M. Mason see patients?
- Medicare's clinician data lists 1 practice location in Wildomar, CA. Call before your visit to confirm the address.
- What is James M. Mason's specialty?
- Medicare lists Radiation Oncology as the primary specialty.
- Does James M. Mason accept Medicare assignment?
- Yes. Medicare's clinician data says James M. Mason 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 James M. Mason?
- (951) 696-0679, as listed in official Medicare / NPI Registry data.
- What is James M. Mason's NPI number?
- 1902955818. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Practice locations
Addresses where James M. Mason is enrolled with Medicare (CMS data updated 2026-10-02).
- 36450 Inland Valley Dr, Suite 101Wildomar, CA 92595 (951) 696‑0679
Group practices
Medicare enrollment lists James M. Mason as a member of this group (CMS data updated 2026-10-02).
- City of Hope Medical Foundation982 clinicians in the group
Specialties
- Radiation Oncologyprimary
Other radiation oncologists in California
Clinicians with the same Medicare primary specialty in California — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Wayne State University School Of Medicine |
| Graduation year | 1988 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1902955818 |
| 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
- 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