Quick answers
- Which hospitals does Mark A. Walshauser work at?
- Medicare's official clinician data lists Mark A. Walshauser at 5 hospitals: HSHS St Elizabeth's Hospital, Sparta Community Hospital, St Johns Hospital, St Joseph's Hospital and St Josephs Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Mark A. Walshauser see patients?
- Medicare's clinician data lists 2 practice locations, including Highland, IL and O Fallon, IL. Call before your visit to confirm the address.
- What is Mark A. Walshauser's specialty?
- Medicare lists Hematology/Oncology as the primary specialty.
- Does Mark A. Walshauser accept Medicare assignment?
- Yes. Medicare's clinician data says Mark A. Walshauser 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 Mark A. Walshauser?
- (618) 651-2888, as listed in official Medicare / NPI Registry data.
- What is Mark A. Walshauser's NPI number?
- 1306020664. 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 A. Walshauser works
Medicare's Facility Affiliation Data lists Mark A. Walshauser at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- HSHS St Elizabeth's HospitalO Fallon, IL · Acute Care Hospital · CCN 140187
- Sparta Community HospitalSparta, IL · Critical Access Hospital · CCN 141349
- St Johns HospitalSpringfield, IL · Acute Care Hospital · CCN 140053
- St Joseph's HospitalHighland, IL · Critical Access Hospital · CCN 141336
- St Josephs HospitalBreese, IL · Acute Care Hospital · CCN 140145
Practice locations
Addresses where Mark A. Walshauser is enrolled with Medicare (CMS data updated 2026-10-02).
- 12860 Troxler Ave, Suite 135Highland, IL 62249 (618) 651‑2888
- 321 Regency Park, Suite 100O Fallon, IL 62269 (618) 416‑7970
Group practices
Medicare enrollment lists Mark A. Walshauser as a member of this group (CMS data updated 2026-10-02).
- Cancer Care Specialists of Central Illinois SC31 clinicians in the group
Specialties
- Hematology/Oncologyprimary
Other hematologist-oncologists in Illinois
Clinicians with the same Medicare primary specialty in Illinois — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 2006 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1306020664 |
| 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