Registry data as of Aug 27, 2026

Mark Walker, M.D.

Psychiatry Physician · Chicago, IL

Mark Walker, M.D. is a psychiatry physician with a practice address in Chicago, Illinois, and NPI 1265561724, issued on Mar 2, 2007. Check the license (Illinois 36-063569, as entered in NPPES) 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 2024 · method · Verify with CMS →

NPPES recordas of Aug 27, 2026
1265561724
Name
Mark Walker
Credential
M.D.
Primary taxonomy
Psychiatry Physician 2084P0800X
License number
36-063569 IL
Self-reported in NPPES; status is on the state search
Practice location
1 E Wacker Dr, Chicago, IL 60601
Phone
(312) 908-7878
Enumerated
Mar 2, 2007
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 1 E Wacker Dr

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

  1. Wendewessen Amde, M.D.Ophthalmology Physician1386837474
  2. Richard Harris, M.D.Psychiatry Physician1285701276
  3. Fredric Levy, M.D.Psychiatry Physician1659373165
  4. Douglas Wilkerson, M. D.Psychoanalysis Psychologist1639293798

Verify Mark Walker in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersIllinois Department of Financial and Professional Regulation
    Search for license 36-063569
    Check 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.

89% fewer Medicare Part D claims than the average psychiatry physician in 2024

114 Medicare Part D claims for 13 beneficiaries, against an average of 1,000 among the 35,054 providers of this specialty who prescribed in Part D. Brand-name drugs were 0% of claims.

  1. Mark Walker114
  2. Specialty average1,000

Most prescribed

  1. Sertraline Hcl20 claims
  2. Escitalopram Oxalate18 claims
  3. Bupropion Xl14 claims
  4. Lorazepam12 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.

Industry payments in 2024: $107.73

1 payment, mostly food and beverage; the largest payer was Tolmar, Inc. The 13,693 providers of this specialty with any payment received $4,954.93 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.

  1. Mark Walker$107.73
  2. Specialty average$4,954.93

Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.

841 psychiatry physician records list a practice address in Chicago

They are 841 of the 63,379 NPPES records with a practice address in Chicago, and 2,147 psychiatry physician records in Illinois.

Other psychiatry physician records in Illinois

  1. Alexandra Aaronson, M.D.Chicago, IL1881937928
  2. Anthony Abadir, MDOak Park, IL1295312551
  3. Huma Abbas, M.D.Aurora, IL1609039163
  4. Jeff Abbott, M.D.Chicago, IL1265887509
  5. Kathryn AbbottChicago, IL1295537561
  6. Gil Abelita, MDBloomington, IL1619986551
  7. Dinuk Abeysekera, M.D.North Chicago, IL1366616534
  8. Patrick Abler, DOSpringfield, IL1770158537
  9. Rohit Abraham, MD, MPH, MATChicago, IL1013478932
  10. Richard AbramsChicago, IL1003992413

Common questions

What is Mark Walker, M.D.'s NPI number?

Mark Walker, M.D.'s National Provider Identifier (NPI) is 1265561724, issued on Mar 2, 2007. An NPI identifies a provider in billing; it is not a license.

Where is Mark Walker, M.D. located?

The NPPES record lists a practice address at 1 E Wacker Dr, Chicago, IL, 60601. Phone: (312) 908-7878. Providers update this record themselves, so call before visiting.

How can I verify Mark Walker, M.D.'s license?

NPPES lists Illinois license number 36-063569, 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 Walker, M.D. prescribe under Medicare Part D?

In 2024, Mark Walker, M.D. had 114 Medicare Part D claims for 13 beneficiaries; the average among psychiatry physician prescribers was 1,000. 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.

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) 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 27, 2026.