Quick answers
- Which hospitals does Eugene S. Ahn work at?
- Medicare's official clinician data lists Eugene S. Ahn at 3 hospitals: Adventist Health Simi Valley, Community Memorial Hospital - Ventura and Los Robles Hospital & Medical Center. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Eugene S. Ahn see patients?
- Medicare's clinician data lists 4 practice locations, including Simi Valley, CA and Ventura, CA. Call before your visit to confirm the address.
- What is Eugene S. Ahn's specialty?
- Medicare lists Radiation Oncology as the primary specialty.
- Does Eugene S. Ahn accept Medicare assignment?
- Yes. Medicare's clinician data says Eugene S. Ahn 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 Eugene S. Ahn?
- (805) 306-0304, as listed in official Medicare / NPI Registry data.
- What is Eugene S. Ahn's NPI number?
- 1912999533. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Eugene S. Ahn works
Medicare's Facility Affiliation Data lists Eugene S. Ahn at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Adventist Health Simi ValleySimi Valley, CA · Acute Care Hospital · CCN 050236
- Community Memorial Hospital - VenturaVentura, CA · Acute Care Hospital · CCN 050394
- Los Robles Hospital & Medical CenterThousand Oaks, CA · Acute Care Hospital · CCN 050549
Practice locations
Addresses where Eugene S. Ahn is enrolled with Medicare (CMS data updated 2026-10-02).
- 124 Macaw LnSimi Valley, CA 93065 (805) 306‑0304
- 2900 Loma Vista Rd, Suite 100Ventura, CA 93003 (805) 648‑5191
- 2985 N Sycamore Dr, Simi Valley Radiation Oncology MediSimi Valley, CA 93065 (805) 584‑6611
- 2985 Sycamore DrSimi Valley, CA 93065 (805) 584‑6611
Group practices
Medicare enrollment lists Eugene S. Ahn as a member of these groups (CMS data updated 2026-10-02).
- Adventist Health Physicians Network628 clinicians in the group
- Coastal Radiation Oncology Medical Group, Inc.11 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 | New York University School Of Medicine |
| Graduation year | 1998 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1912999533 |
| 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