Quick answers
- Where does William Marx see patients?
- Medicare's clinician data lists 2 practice locations, including New York, NY and Commack, NY. Call before your visit to confirm the address.
- What is William Marx's specialty?
- Medicare lists Anesthesiology as the primary specialty.
- Does William Marx accept Medicare assignment?
- Yes. Medicare's clinician data says William Marx 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 William Marx?
- (212) 639-2000, as listed in official Medicare / NPI Registry data.
- What is William Marx's NPI number?
- 1205802311. 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 William Marx is enrolled with Medicare (CMS data updated 2026-10-02).
- 1275 York AveNew York, NY 10065 (212) 639‑2000
- 650 Commack RdCommack, NY 11725 (631) 623‑4034
Group practices
Medicare enrollment lists William Marx as a member of these groups (CMS data updated 2026-10-02).
- Memorial Anesthesiology Group302 clinicians in the group
- MSKCC Regional Network136 clinicians in the group
Specialties
- Anesthesiologyprimary
Other anesthesiologists in New York
Clinicians with the same Medicare primary specialty in New York, NY — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 1973 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1205802311 |
| 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