Quick answers
- Where does James J. Koster see patients?
- Medicare's clinician data lists 1 practice location in Phoenix, AZ. Call before your visit to confirm the address.
- What is James J. Koster's specialty?
- Medicare lists Ophthalmology as the primary specialty.
- Does James J. Koster accept Medicare assignment?
- Yes. Medicare's clinician data says James J. Koster 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 J. Koster?
- (602) 254-7255, as listed in official Medicare / NPI Registry data.
- What is James J. Koster's NPI number?
- 1851387344. 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 J. Koster is enrolled with Medicare (CMS data updated 2026-10-02).
- 300 E Osborn Rd, Suite 100Phoenix, AZ 85012 (602) 254‑7255
Group practices
Medicare enrollment lists James J. Koster as a member of this group (CMS data updated 2026-10-02).
- Associated Ophthalmologists Ltd16 clinicians in the group
Specialties
- Ophthalmologyprimary
Other ophthalmologists in Phoenix
Clinicians with the same Medicare primary specialty in Phoenix, AZ — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Arizona College Of Medicine |
| Graduation year | 1999 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1851387344 |
| 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