Quick answers
- Does Jeffrey K. Shimoyama accept Medicare assignment?
- Yes. Medicare's clinician data says Jeffrey K. Shimoyama accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- How many Medicare patients does Jeffrey K. Shimoyama see?
- In 2024, CMS data shows 12 Original Medicare patients and 12 services for Jeffrey K. Shimoyama. This counts Original Medicare only and measures volume, not quality.
- What is Jeffrey K. Shimoyama's NPI number?
- 1245307255. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Medicare activity in 2024
Official CMS public-use data for Jeffrey K. Shimoyama, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.
| Original Medicare patients | 12 |
|---|---|
| Services billed to Medicare | 12 |
| Different services or procedures | 3 |
| Participating Medicare provider | Yes |
| Average age of these patients | 70 |
Practice locations
Addresses where Jeffrey K. Shimoyama is enrolled with Medicare (CMS data updated October 2, 2026).
- 6041 Cadillac AveLos Angeles, CA 90034 (800) 954‑8000
Group practices
Medicare enrollment lists Jeffrey K. Shimoyama as a member of this group (CMS data updated October 2, 2026).
- Southern California Permanente Medical Group11,293 clinicians in the group
Specialties
- Internal Medicineprimary
Other internal medicine doctors in Los Angeles
Clinicians with the same Medicare primary specialty in Los Angeles, CA — not a recommendation.
Other clinicians in Southern California Permanente Medical Group
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of California, Davis School Of Medicine |
| Graduation year | 1987 (39 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1245307255 |
| 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 October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- 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