Quick answers
- Does Stephen P. O'Mahony accept Medicare assignment?
- Yes. Medicare's clinician data says Stephen P. O'Mahony 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.
- What is Stephen P. O'Mahony's NPI number?
- 1144291162. 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 Stephen P. O'Mahony is enrolled with Medicare (CMS data updated October 2, 2026).
- 101 Old Short Hills Rd, Suite 106West Orange, NJ 07052 (973) 322‑6256
- 94 Old Short Hills RdLivingston, NJ 07039 (973) 322‑5195
Group practices
Medicare enrollment lists Stephen P. O'Mahony as a member of this group (CMS data updated October 2, 2026).
- RWJBH Primary Care Services267 clinicians in the group
Specialties
- Internal Medicineprimary
Other internal medicine doctors in West Orange
Clinicians with the same Medicare primary specialty in West Orange, NJ — not a recommendation.
Other clinicians in RWJBH Primary Care Services
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Connecticut School Of Medicine |
| Graduation year | 1996 (30 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1144291162 |
| 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
- 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