Registry data as of Aug 27, 2026

John Demask, D.O.

Family Medicine Physician · Minooka, IL

John Demask, D.O. is a family medicine physician with a practice address in Minooka, Illinois, and NPI 1174501134, issued on Jan 9, 2006. Check the license on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.

Record from CMS NPPES, loaded Aug 27, 2026 · Medicare files 2023 and 2024 · method · Verify with CMS →

NPPES recordas of Aug 27, 2026
1174501134
Name
John Demask
Credential
D.O.
Primary taxonomy
Family Medicine Physician 207Q00000X
Practice location
201 S Wabena Ave, Minooka, IL 60447
Phone
(815) 467-1518
Enumerated
Jan 9, 2006
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). A record is not a license: verify it with the state board.
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Also registered at 201 S Wabena Ave

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Muhammed Khan, M.D.Internal Medicine Physician1386678183

Verify John Demask in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersIllinois Department of Financial and Professional RegulationCheck the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS, AOA, NCCPA, AANPNot checked
Open the Illinois license search

PlainDoctor does not match the HHS-OIG exclusion list to individual records: most entries carry no NPI. Search the OIG exclusion list by name.

22% more Medicare Part D claims than the average family medicine physician in 2024

4,293 Medicare Part D claims for 303 beneficiaries, against an average of 3,519 among the 111,126 providers of this specialty who prescribed in Part D. 166 claims were for opioids.

  1. John Demask4,293
  2. Specialty average3,519

Most prescribed

  1. Amlodipine Besylate253 claims
  2. Levothyroxine Sodium205 claims
  3. Hydrochlorothiazide204 claims
  4. Atorvastatin Calcium193 claims
  5. Lisinopril187 claims
  6. Metformin Hcl167 claims

Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.

3 family medicine physician records list a Minooka practice address

They are 3 of the 104 NPPES records with a Minooka practice address, and 5,925 family medicine physician records in Illinois.

Other family medicine physician records in Illinois

  1. Jon Aagaard, MDWheaton, IL1750496923
  2. Napoleon Abando, MDWoodstock, IL1003972753
  3. Nikka Abaricia, MDChicago, IL1790366342
  4. Mohemmed AbbasChicago, IL1609612522
  5. Muhammad AbbasAlton, IL1588341556
  6. Syed AbbasWest Dundee, IL1972733103
  7. Stefanie AbbottMaywood, IL1861137457
  8. Roann Abdeladl, MDEvanston, IL1437087103
  9. Ashraf Abdeljaber, M.DNormal, IL1023472636
  10. Ahmed Abdelkader, MDChicago, IL1659104230

Common questions

What is John Demask, D.O.'s NPI number?

John Demask, D.O.'s National Provider Identifier (NPI) is 1174501134, issued on Jan 9, 2006. An NPI identifies a provider in billing; it is not a license.

Where is John Demask, D.O. located?

The NPPES record lists a practice address at 201 S Wabena Ave, Minooka, IL, 60447. Phone: (815) 467-1518. Providers update this record themselves, so call before visiting.

How can I verify John Demask, D.O.'s license?

Search the Illinois Department of Financial and Professional Regulation at https://idfpr.illinois.gov/checklicense.html. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.

How much does John Demask, D.O. prescribe under Medicare Part D?

In 2024, John Demask, D.O. had 4,293 Medicare Part D claims for 303 beneficiaries; the average among family medicine physician prescribers was 3,519. Part D covers Medicare prescriptions only.

Source: CMS National Plan and Provider Enumeration System (NPPES), loaded Aug 27, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.

Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 27, 2026.