Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Gregory Wayne Grzesik, D.O.

Hospitalist Physician in Weston, WI · enumerated 2013.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1316389372

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Registry record

Entity type Individual (Type 1)

Name Dr. Gregory Wayne Grzesik

Credential D.O.

Sex Male

Practice address 3400 Ministry Pkwy, Weston, WI, 54476

Phone (715) 393-1220

Enumeration date Jul 18, 2013

Last updated in NPPES Jun 18, 2025

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 65797-21 (WI) Secondary

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 125-062888 (IL) Secondary

208M00000X Hospitalist Physician Allopathic & Osteopathic Physicians · License 65797 (WI) Primary

DO · Doctor of Osteopathic Medicine: A fully licensed physician trained in osteopathic medical schools, with the same practice rights as an MD. About the DO credential

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

What is the NPI number for Gregory Grzesik?

The National Provider Identifier (NPI) for Gregory Grzesik is 1316389372, a Type 1 (individual) record in the CMS NPPES registry.

Where does Gregory Grzesik practice?

The practice location on file with NPPES is in Weston, WI. Providers can have multiple locations; NPPES lists the primary practice address.

Other providers at this practice address

Browse all →

Awad El-Magbri Nephrology Physician · Weston, WI NPI 1740281153 Nicolaus Schermer Certified Registered Nurse Anesthetist · Weston, WI NPI 1730175480 Kshamata Shalini Internal Medicine Physician · Weston, WI NPI 1023099306 Srinivas Kolla Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician · Weston, WI NPI 1235100397 Holly Worzalla Speech-Language Pathologist · Weston, WI NPI 1467420497 David White Anesthesiology Physician · Weston, WI NPI 1841259751 Gregory Gilles Anesthesiology Physician · Weston, WI NPI 1376500082 Victoria Burger Certified Registered Nurse Anesthetist · Weston, WI NPI 1811940257

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2025-06-18.