Quick answers
- Where does Gregory B. Marsh see patients?
- Medicare's clinician data lists 2 practice locations, including Seattle, WA. Call before your visit to confirm the address.
- What is Gregory B. Marsh's specialty?
- Medicare lists Anesthesiology as the primary specialty.
- Does Gregory B. Marsh accept Medicare assignment?
- Yes. Medicare's clinician data says Gregory B. Marsh 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 Gregory B. Marsh?
- (206) 625-0578, as listed in official Medicare / NPI Registry data.
- What is Gregory B. Marsh's NPI number?
- 1114952009. 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 Gregory B. Marsh is enrolled with Medicare (CMS data updated 2026-10-02).
- 1229 Madison St, Suite 1440Seattle, WA 98104 (206) 625‑0578
- 747 BroadwaySeattle, WA 98122 (206) 386‑2742
Group practices
Medicare enrollment lists Gregory B. Marsh as a member of this group (CMS data updated 2026-10-02).
- Physicians Anesthesia Service PLLC172 clinicians in the group
Specialties
- Anesthesiologyprimary
Other anesthesiologists in Seattle
Clinicians with the same Medicare primary specialty in Seattle, WA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Washington School Of Medicine |
| Graduation year | 1988 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1114952009 |
| 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