Quick answers
- Which hospitals does Mahmoud M. El Sayed work at?
- Medicare's official clinician data lists Mahmoud M. El Sayed at 3 hospitals: HSHS St Elizabeth's Hospital, SSM Health Saint Louis University Hospital and St Josephs Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Mahmoud M. El Sayed see patients?
- Medicare's clinician data lists 3 practice locations, including O Fallon, IL, Greenville, IL and Effingham, IL. Call before your visit to confirm the address.
- What is Mahmoud M. El Sayed's specialty?
- Medicare lists Critical Care (Intensivists) as the primary specialty, and also Internal Medicine.
- Does Mahmoud M. El Sayed accept Medicare assignment?
- Yes. Medicare's clinician data says Mahmoud M. El Sayed 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 Mahmoud M. El Sayed?
- (618) 234-2120, as listed in official Medicare / NPI Registry data.
- What is Mahmoud M. El Sayed's NPI number?
- 1982618856. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Mahmoud M. El Sayed works
Medicare's Facility Affiliation Data lists Mahmoud M. El Sayed 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
- SSM Health Saint Louis University HospitalSaint Louis, MO · Acute Care Hospital · CCN 260105
- St Josephs HospitalBreese, IL · Acute Care Hospital · CCN 140145
Practice locations
Addresses where Mahmoud M. El Sayed is enrolled with Medicare (CMS data updated 2026-10-02).
- 1 Saint Elizabeth BlvdO Fallon, IL 62269 (618) 234‑2120
- 200 Health Care DrGreenville, IL 62246 (618) 664‑1230
- 503 N Maple StEffingham, IL 62401 (217) 347‑1236
Group practices
Medicare enrollment lists Mahmoud M. El Sayed as a member of this group (CMS data updated 2026-10-02).
- Cep America Illinois Intensivists48 clinicians in the group
Specialties
Find other Critical Care (Intensivists) doctors in Illinois →
Other critical care doctors in O Fallon
Clinicians with the same Medicare primary specialty in O Fallon, IL — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 1999 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1982618856 |
| 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