Quick answers
- Which hospitals does Mark D. Horneffer work at?
- Medicare's official clinician data lists Mark D. Horneffer at 2 hospitals: Ascension Columbia St Marys Hospital Milwaukee and Ascension SE Wisconsin Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Mark D. Horneffer see patients?
- Medicare's clinician data lists 3 practice locations, including Wauwatosa, WI, Brookfield, WI and West Allis, WI. Call before your visit to confirm the address.
- What is Mark D. Horneffer's specialty?
- Medicare lists Internal Medicine as the primary specialty.
- Does Mark D. Horneffer accept Medicare assignment?
- Yes. Medicare's clinician data says Mark D. Horneffer 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.
- Does Mark D. Horneffer offer telehealth?
- Medicare's clinician data says Mark D. Horneffer offers telehealth services. Ask the office which visits can be done by video or phone.
- What is the phone number for Mark D. Horneffer?
- (414) 464-4460, as listed in official Medicare / NPI Registry data.
- What is Mark D. Horneffer's NPI number?
- 1710928965. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Mark D. Horneffer works
Medicare's Facility Affiliation Data lists Mark D. Horneffer at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Ascension Columbia St Marys Hospital MilwaukeeMilwaukee, WI · Acute Care Hospital · CCN 520051
- Ascension SE Wisconsin HospitalMilwaukee, WI · Acute Care Hospital · CCN 520136
Practice locations
Addresses where Mark D. Horneffer is enrolled with Medicare (CMS data updated 2026-10-02).
- 10950 W Capitol DrWauwatosa, WI 53222 (414) 464‑4460
- 13950 W Capitol DrBrookfield, WI 53005 (414) 464‑4460
- 801 S 70th StWest Allis, WI 53214 (414) 773‑6600
Group practices
Medicare enrollment lists Mark D. Horneffer as a member of this group (CMS data updated 2026-10-02).
- Columbia St Marys Hospital Milwaukee Inc306 clinicians in the group
Specialties
- Internal Medicineprimary
Other internal medicine doctors in Wauwatosa
Clinicians with the same Medicare primary specialty in Wauwatosa, WI — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Michigan Medical School |
| Graduation year | 1990 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1710928965 |
| 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