Mark J. Tatara, MD
Internal Medicine Physician · Downers Grove, IL
Mark J. Tatara, MD is an internal medicine physician with a practice address in Downers Grove, Illinois, and NPI 1043256324, issued on Jun 22, 2006. Check the license (Illinois 036-077438, as entered in NPPES) on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.
- Name
- Mark J. Tatara
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 036-077438 IL
Self-reported in NPPES; status is on the state search - Practice location
- 6840 Main St Ste 200, Downers Grove, IL 60516
- Phone
- (630) 869-5382
- Enumerated
- Jun 22, 2006
- Record last updated
- Dec 23, 2021 (not updated in 5 years: call before relying on the address or phone)
- Fax
- (630) 869-5383
- Medicaid IDs
- 0795794 OH
100355690 IN - Medicare enrollment
- Enrolled (PECOS I20170608002571); accepts Medicare assignment
- Medical or professional school
- Chicago College Of Medicine And Surgery, 1986
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 7,238 in Illinois → Look up another NPI →
Also registered at 6840 Main St Ste 200
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Carlo Prades, MDInternal Medicine Physician1457880080
- Lyba Zia, MDObstetrics & Gynecology Physician1861070914
Verify Mark J. Tatara in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersIllinois Department of Financial and Professional Regulation
Search for license 036-077438Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
2.8 times the Medicare Part D claims of the average internal medicine physician in 2024
8,761 Medicare Part D claims for 707 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 10% of claims. 107 claims were for opioids.
Most prescribed
- Atorvastatin Calcium736 claims
- Amlodipine Besylate414 claims
- Lisinopril339 claims
- Metformin Hcl300 claims
- Levothyroxine Sodium295 claims
- Hydrochlorothiazide278 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.
Bills Medicare through one group practice
- Advocate Health And Hospitals CorporationHuntley, IL
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Mark J. Tatara among 7,238 internal medicine physician records in Illinois
Mark J. Tatara, MD is one of 7,238 internal medicine physician records with a practice address in Illinois. 73% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 7% of them.
- NPI issued2006 · 7% of these records are older, 61% newer
- In a Medicare fileYes · 73% of these records are
- In the CMS Doctors and Clinicians fileYes · 50% of these records are
- Graduated1986 · median 2003 among the 3,580 with a school on file
- Record last updated2021 · 47% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
33 internal medicine physician records list a practice address in Downers Grove
They are 33 of the 1,899 NPPES records with a practice address in Downers Grove, and 7,238 internal medicine physician records in Illinois.
All 7,238 in Illinois → Every provider in Downers Grove → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Carlo Prades, MDDowners Grove, IL 605161457880080
- Elissa Adatya, M.D.Downers Grove, IL 605151871784553
- Joanne Cheung, M.D.Downers Grove, IL 605151811165384
- Weiser Cordero, M.D.Downers Grove, IL 605151063689719
- Mary Anne Damiani, D.O.Woodridge, IL 605171174578934
- Ashok Dholakia, MDWoodridge, IL 605171568451490
- Sara Doss, M.D.Woodridge, IL 605171770747743
- Subuhi Humera, D.ODowners Grove, IL 605151639435837
Common questions
What is Mark J. Tatara, MD's NPI number?
Mark J. Tatara, MD's National Provider Identifier (NPI) is 1043256324, issued on Jun 22, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Mark J. Tatara, MD located?
The NPPES record lists a practice address at 6840 Main St Ste 200, Downers Grove, IL, 60516. Phone: (630) 869-5382. Providers update this record themselves, so call before visiting.
How can I verify Mark J. Tatara, MD's license?
NPPES lists Illinois license number 036-077438, as entered by the provider. 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 Mark J. Tatara, MD prescribe under Medicare Part D?
In 2024, Mark J. Tatara, MD had 8,761 Medicare Part D claims for 707 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 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.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.