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

Dr. Gregory Grimberg, MD

Individual provider Surgery Physician · NPI 1104245307

Dr. Gregory Grimberg, MD practises General Surgery in Mason City, Iowa. Graduated from State University of New York Downstate Medical Center in 2014, 12 years ago. Practices with North Iowa Mercy Clinics, a 300-clinician group, works from 2 locations and accepts Medicare assignment. Licensed in Iowa and Maryland.

Years since qualifying
12
Trained at
State University of New York Downstate Medical Center
Licensed in
IA, MD
In the registry since
2014
Specialties on file
2
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

250 S Crescent Dr
Mason City, IA 50401-2926
Phone: (641) 494-5300
Fax: (641) 494-5321
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 4940 Eastern Ave Rm 3933d, Baltimore, MD 21224-2735 — (410) 550-6875

Specialties & licences

Surgery Physician (primary) Taxonomy 208600000X · Licence MD-47527 (IA)
Surgery Physician Taxonomy 208600000X · Licence D86982 (MD)

Record details

NPI number1104245307
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedApril 15, 2014
Last updated in NPPESAugust 28, 2020
Certification dateAugust 28, 2020

Medicare enrollment

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

Medicare specialtyGENERAL SURGERY
Medical schoolSTATE UNIVERSITY OF NEW YORK DOWNSTATE MEDICAL CENTER
Graduated 2014 (12 years in practice)
Group practice North Iowa Mercy Clinics — 300 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations6 on file with Medicare

Procedures

From CMS Care Compare, which counts the procedures a clinician billed to Original Medicare and Medicare Advantage over a recent 12-month period. CMS reports a fixed list of common procedures, so this is not everything the clinician does. Counts of 10 or fewer are given as a range, because CMS withholds small numbers.

Upper gastrointestinal (GI) endoscopy for acid reflux 212 times · 91st percentile
Colonoscopy 15 times · 44th percentile
Removal of skin lesions 1–10 times

The percentile compares how often this clinician performed the procedure with other clinicians who performed it, as CMS calculates it. It measures volume, not outcomes or skill.

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 patients135
Services billed 1,349 a service is one billed item, such as a visit, a test or a procedure
Average patient age72

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.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $276 7 payments · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

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

Colleagues at North Iowa Mercy Clinics

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 300 clinicians in the practice; 12 are shown here.

Other providers in Mason City