Quick answers
- Which hospitals does Stephen T. Onesti work at?
- Medicare's official clinician data lists Stephen T. Onesti at 2 hospitals: Mercy Medical Center and Mount Sinai South Nassau. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Stephen T. Onesti see patients?
- Medicare's clinician data lists 2 practice locations, including Rockville Centre, NY and New Hyde Park, NY. Call before your visit to confirm the address.
- What is Stephen T. Onesti's specialty?
- Medicare lists Neurosurgery as the primary specialty.
- Does Stephen T. Onesti accept Medicare assignment?
- Yes. Medicare's clinician data says Stephen T. Onesti 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 Stephen T. Onesti's NPI number?
- 1114912458. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Stephen T. Onesti works
Medicare's Facility Affiliation Data lists Stephen T. Onesti at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Mercy Medical CenterRockville Centre, NY · Acute Care Hospital · CCN 330259
- Mount Sinai South NassauOceanside, NY · Acute Care Hospital · CCN 330198
Practice locations
Addresses where Stephen T. Onesti is enrolled with Medicare (CMS data updated 2026-10-02).
- 100 Merrick Rd, 128wRockville Centre, NY 11570
- 1991 Marcus Ave, Suite 108New Hyde Park, NY 11042
Group practices
Medicare enrollment lists Stephen T. Onesti as a member of this group (CMS data updated 2026-10-02).
- Neurological Surgery Practice of Long Island PLLC14 clinicians in the group
Specialties
- Neurosurgeryprimary
Other neurosurgeons in Rockville Centre
Clinicians with the same Medicare primary specialty in Rockville Centre, NY — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Harvard Medical School |
| Graduation year | 1986 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1114912458 |
| 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