Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

Dr. Gregory Wayne Grzesik, DO

Individual provider Internal Medicine Physician · NPI 1316389372

Dr. Gregory Wayne Grzesik, DO is a Hospitalist in Weston, Wisconsin. Graduated from Lake Erie College of Osteopathic Medicine, Erie in 2013, 13 years ago. Practices with Mchs Hospitals Inc, a 1,194-clinician group, works from 2 locations and accepts Medicare assignment. Licensed in Illinois and Wisconsin.

Years since qualifying
13
Trained at
Lake Erie College of Osteopathic Medicine, Erie
Licensed in
IL, WI
In the registry since
2013
Specialties on file
3
What do these letters mean?
DO — Doctor of Osteopathic Medicine
A fully licensed physician, trained like an MD with additional musculoskeletal training. Equivalent practice rights in all 50 states.

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Practice location Address checks out

3400 Ministry Pkwy
Weston, WI 54476-5220
Phone: (715) 393-1220
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 2251 N Shore Dr, Rhinelander, WI 54501-6710 — (715) 361-4700

Specialties & licences

Hospitalist Physician (primary) Taxonomy 208M00000X · Licence 65797 (WI)
Internal Medicine Physician Taxonomy 207R00000X · Licence 65797-21 (WI)
Internal Medicine Physician Taxonomy 207R00000X · Licence 125-062888 (IL)

Record details

NPI number1316389372
Entity typeIndividual (Type 1)
GenderMale
Credentials DO
Sole proprietorNo
NPI enumeratedJuly 18, 2013
Last updated in NPPESJune 18, 2025
Certification dateJune 18, 2025

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyHOSPITALIST
Medical schoolLAKE ERIE COLLEGE OF OSTEOPATHIC MEDICINE, ERIE
Graduated 2013 (13 years in practice)
Group practice McHs Hospitals Inc — 1194 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations3 on file with Medicare

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients75
Services billed 211 a service is one billed item, such as a visit, a test or a procedure
Average patient age75

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician. Those with a page here are linked.

Colleagues at Mchs Hospitals Inc

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 1194 clinicians in the practice; 12 are shown here.

Other providers in Weston