Cassidy Williams, DO
Surgery Physician · Chicago, IL
Cassidy Williams, DO is a surgery physician with a practice address in Chicago, Illinois, and NPI 1578211140, issued on Mar 14, 2022. Check the license (Illinois 125.082539, as entered in NPPES) on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.
- Name
- Cassidy Williams
- Credential
- DO
- Primary taxonomy
- Surgery Physician 208600000X
- License number
- 125.082539 IL
Self-reported in NPPES; status is on the state search - Practice location
- 600 S Paulina St, Chicago, IL 60612
- Phone
- (312) 942-7100
- Enumerated
- Mar 14, 2022
- Record last updated
- Sep 20, 2023
- Entity
- Type 1 · individual
8 nearest surgery physician records → All 1,520 in Illinois → Look up another NPI →
Also registered at 600 S Paulina St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Neelum Aggarwal, M.D.Neurology Physician1154450799
Verify Cassidy Williams 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 125.082539Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
93% fewer Medicare Part D claims than the average surgery physician in 2024
11 Medicare Part D claims, against an average of 147 among the 20,115 providers of this specialty who prescribed in Part D. Brand-name drugs were 0% of 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: $496.15
4 payments; by number, the most common kind was food and beverage; the largest payer was Boston Scientific Corporation. The 17,103 providers of this specialty with any payment received $3,513.80 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Cassidy Williams among 1,520 surgery physician records in Illinois
Cassidy Williams, DO is one of 1,520 surgery physician records with a practice address in Illinois. 66% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2022, is newer than 82% of them.
- NPI issued2022 · 82% of these records are older, 13% newer
- In a Medicare fileYes · 66% of these records are
- In the CMS Doctors and Clinicians fileNo · 43% of these records are
- Record last updated2023 · 49% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 208600000X and a Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Surgery Physician providers in Illinois
There are 1,520 surgery physician records in Illinois.
All 1,520 in Illinois → Every provider in Chicago → Surgery Physician nationwide →
The 8 surgery physician records with the nearest ZIP codes
- Amelia BartholomewChicago, IL 606121447356886
- Steven Bines, MDChicago, IL 606121609833086
- Steven Bonomo, MDChicago, IL 606121861478893
- Diane Drugas, M.D.Chicago, IL 606121457436776
- Burnetta Herron, M.D.Chicago, IL 606121841211513
- Chad Kessler, MDChicago, IL 606121386624948
- Katherine Liu, M.D.Chicago, IL 606121184673832
- Elizabeth Marcus, MDChicago, IL 606121457464638
Common questions
What is Cassidy Williams, DO's NPI number?
Cassidy Williams, DO's National Provider Identifier (NPI) is 1578211140, issued on Mar 14, 2022. An NPI identifies a provider in billing; it is not a license.
Where is Cassidy Williams, DO located?
The NPPES record lists a practice address at 600 S Paulina St, Chicago, IL, 60612. Phone: (312) 942-7100. Providers update this record themselves, so call before visiting.
How can I verify Cassidy Williams, DO's license?
NPPES lists Illinois license number 125.082539, 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 Cassidy Williams, DO prescribe under Medicare Part D?
In 2024, Cassidy Williams, DO had 11 Medicare Part D claims; the average among surgery physician prescribers was 147. 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.