Quick answers
- Which hospitals does Todd A. Mahr work at?
- Medicare's official clinician data lists Todd A. Mahr at 1 hospital: Gundersen Lutheran Medical Center. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Todd A. Mahr see patients?
- Medicare's clinician data lists 5 practice locations, including Winona, MN, Onalaska, WI and Decorah, IA. Call before your visit to confirm the address.
- What is Todd A. Mahr's specialty?
- Medicare lists Allergy/Immunology as the primary specialty.
- Does Todd A. Mahr accept Medicare assignment?
- Yes. Medicare's clinician data says Todd A. Mahr 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 Todd A. Mahr?
- (507) 615-0600, as listed in official Medicare / NPI Registry data.
- What is Todd A. Mahr's NPI number?
- 1659374411. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Todd A. Mahr works
Medicare's Facility Affiliation Data lists Todd A. Mahr at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Gundersen Lutheran Medical CenterLa Crosse, WI · Acute Care Hospital · CCN 520087
Practice locations
Addresses where Todd A. Mahr is enrolled with Medicare (CMS data updated 2026-10-02).
- 1122 W Hwy 61Winona, MN 55987 (507) 615‑0600
- 1600 Main StOnalaska, WI 54650 (608) 783‑4681
- 1830 State Hwy 9, Suite 100Decorah, IA 52101 (563) 382‑3140
- 226 2nd St NLacrescent, MN 55947 (507) 895‑6610
- 3111 Gundersen DrOnalaska, WI 54650 (608) 782‑7300
Group practices
Medicare enrollment lists Todd A. Mahr as a member of these groups (CMS data updated 2026-10-02).
- Gundersen Lutheran Medical Center Inc895 clinicians in the group
- Gundersen Clinic Ltd418 clinicians in the group
- Gundersen Regional Clinics, LLC53 clinicians in the group
Specialties
- Allergy/Immunologyprimary
Other allergist and immunologists in Minnesota
Clinicians with the same Medicare primary specialty in Minnesota — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Wisconsin School Of Medicine |
| Graduation year | 1984 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1659374411 |
| 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