Quick answers
- Where does Peter G. O'Brien see patients?
- Medicare's clinician data lists 2 practice locations, including Lake Elsinore, CA and Murrieta, CA. Call before your visit to confirm the address.
- What is Peter G. O'Brien's specialty?
- Medicare lists Nurse Practitioner as the primary specialty.
- Does Peter G. O'Brien accept Medicare assignment?
- Yes. Medicare's clinician data says Peter G. O'Brien 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 Peter G. O'Brien?
- (951) 397-4214, as listed in official Medicare / NPI Registry data.
- What is Peter G. O'Brien's NPI number?
- 1639533490. 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 Peter G. O'Brien is enrolled with Medicare (CMS data updated 2026-10-02).
- 31571 Canyon Estates Dr, Suite 100Lake Elsinore, CA 92532 (951) 397‑4214
- 41880 Kalmia St, Suite 100Murrieta, CA 92562 (951) 397‑4226
Group practices
Medicare enrollment lists Peter G. O'Brien as a member of this group (CMS data updated 2026-10-02).
- Southern California Urgent Care Network15 clinicians in the group
Specialties
- Nurse Practitionerprimary
Other nurse practitioners in Lake Elsinore
Clinicians with the same Medicare primary specialty in Lake Elsinore, CA — not a recommendation.
Clinician information
| Credential | NP |
|---|---|
| Graduation year | 2016 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1639533490 |
| 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