Quick answers
- Which hospitals does John R. Nienow work at?
- Medicare's official clinician data lists John R. Nienow at 5 hospitals: California Pacific Medical Center - Mission Bernal…, California Pacific Medical Center- Van Ness Campus, California Pacific Medical Center-Davies Campus Hospital, Novato Community Hospital and UCSF Medical Center. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does John R. Nienow see patients?
- Medicare's clinician data lists 1 practice location in San Francisco, CA. Call before your visit to confirm the address.
- What is John R. Nienow's specialty?
- Medicare lists Internal Medicine as the primary specialty.
- Does John R. Nienow accept Medicare assignment?
- Yes. Medicare's clinician data says John R. Nienow 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 John R. Nienow's NPI number?
- 1861472649. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where John R. Nienow works
Medicare's Facility Affiliation Data lists John R. Nienow at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- California Pacific Medical Center - Mission Bernal…San Francisco, CA · Acute Care Hospital · CCN 050055
- California Pacific Medical Center- Van Ness CampusSan Francisco, CA · Acute Care Hospital · CCN 050047
- California Pacific Medical Center-Davies Campus HospitalSan Francisco, CA · Acute Care Hospital · CCN 050008
- Novato Community HospitalNovato, CA · Acute Care Hospital · CCN 050131
- UCSF Medical CenterSan Francisco, CA · Acute Care Hospital · CCN 050454
Practice locations
Addresses where John R. Nienow is enrolled with Medicare (CMS data updated 2026-10-02).
- 2300 California St, Suite 306San Francisco, CA 94115
Specialties
- Internal Medicineprimary
Other internal medicine doctors in San Francisco
Clinicians with the same Medicare primary specialty in San Francisco, CA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Yale University School Of Medicine |
| Graduation year | 1988 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1861472649 |
| 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