Quick answers
- Which hospitals does William C. Bayer work at?
- Medicare's official clinician data lists William C. Bayer at 5 hospitals: Northwestern Lake Forest Hospital, Northwestern Medicine Central Dupage Hospital, Northwestern Medicine Delnor Community Hospital, Northwestern Medicine McHenry and Palos Community Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does William C. Bayer see patients?
- Medicare's clinician data lists 5 practice locations, including Wheaton, IL, Bloomingdale, IL and Naperville, IL. Call before your visit to confirm the address.
- What is William C. Bayer's specialty?
- Medicare lists Endocrinology as the primary specialty, and also Internal Medicine.
- Does William C. Bayer accept Medicare assignment?
- Yes. Medicare's clinician data says William C. Bayer 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 William C. Bayer offer telehealth?
- Medicare's clinician data says William C. Bayer offers telehealth services. Ask the office which visits can be done by video or phone.
- What is the phone number for William C. Bayer?
- (630) 933-4800, as listed in official Medicare / NPI Registry data.
- What is William C. Bayer's NPI number?
- 1528162898. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where William C. Bayer works
Medicare's Facility Affiliation Data lists William C. Bayer at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Northwestern Lake Forest HospitalLake Forest, IL · Acute Care Hospital · CCN 140130
- Northwestern Medicine Central Dupage HospitalWinfield, IL · Acute Care Hospital · CCN 140242
- Northwestern Medicine Delnor Community HospitalGeneva, IL · Acute Care Hospital · CCN 140211
- Northwestern Medicine McHenryMcHenry, IL · Acute Care Hospital · CCN 140116
- Palos Community HospitalPalos Heights, IL · Acute Care Hospital · CCN 140062
Practice locations
Addresses where William C. Bayer is enrolled with Medicare (CMS data updated 2026-10-02).
- 1800 N Main StWheaton, IL 60187 (630) 933‑4800
- 2001 S Wiesbrook RdWheaton, IL 60189 (630) 614‑4000
- 233 S Gary AveBloomingdale, IL 60108 (630) 208‑6775
- 636 Raymond Dr, Suite 204Naperville, IL 60563 (630) 682‑8700
- 7 Blanchard CirWheaton, IL 60189 (630) 653‑0848
Group practices
Medicare enrollment lists William C. Bayer as a member of this group (CMS data updated 2026-10-02).
- Central Dupage Physician Group1,080 clinicians in the group
Specialties
- Endocrinologyprimary
- Internal Medicinealso
Other endocrinologists in Illinois
Clinicians with the same Medicare primary specialty in Illinois — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Loyola University Of Chicago, Stritch School Of Medicine |
| Graduation year | 1986 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1528162898 |
| 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