REBECCA LYNN WILLIAMS MD, PHD
NPI 1538509294
Surgery - Surgical Oncology in Chicago, IL
About Rebecca Lynn Williams Md, Phd NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
REBECCA LYNN WILLIAMS MD, PHD (NPI 1538509294) is an individual surgical oncology provider in Chicago, Illinois, licensed in Illinois (036165097) and active in the NPI registry since June 2013. She is enrolled in Medicare PECOS, is affiliated with Northwestern Lake Forest Hospital, and maintains a secondary practice location in Madison.
NPPES Registry Identity
Specialties & Licenses 2
Secondary Practice Location 1
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Rebecca Lynn Williams Md, Phd is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignment
Medicare enrollment records show Rebecca Williams reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Carol Stream, IL 60122
- Reassigned Medicare billing, Illinois enrollment
- 4,817 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims 3
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Hospital Affiliations CMS Care Compare 3
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Northwestern Lake Forest Hospital
Acute Care Hospitals · Lake Forest, ILNorthwestern Medicine Central Dupage Hospital
Acute Care Hospitals · Winfield, ILNorthwestern Memorial Hospital
Acute Care Hospitals · Chicago, ILPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 60611 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Medicare Quality Performance CMS QPP · MIPS
Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.
Other Providers at the Same Location NPPES 4
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
CHICAGO, IL 60611
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Rebecca Williams's NPI number?
The NPI number for Rebecca Williams is 1538509294. It was assigned to this individual provider in the NPPES registry on June 26, 2013.
Where is Rebecca Williams located?
Rebecca Williams practices at 675 N Saint Clair St Ste 21-700, Chicago, IL 60611. The listed phone number is (312) 695-0990.
What is Rebecca Williams's specialty?
The primary specialty registered for this NPI is Surgery, specializing in Surgical Oncology, with taxonomy code 2086X0206X.
Is Rebecca Williams enrolled in Medicare?
Yes. Rebecca Williams is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organization bills Medicare for Rebecca Williams's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Rebecca Williams reassigns Medicare benefits to Northwestern Medical Faculty Foundation (Carol Stream, IL). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Rebecca Williams's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
Is Rebecca Williams affiliated with any hospitals?
According to CMS data, Rebecca Williams is affiliated with Northwestern Lake Forest Hospital, Northwestern Medicine Central Dupage Hospital and Northwestern Memorial Hospital.
When was this NPI record last updated?
The NPPES record for Rebecca Williams was last updated on October 26, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 17 days ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Rebecca Lynn Williams, MD, PHD · NPI 1538509294
Surgical Oncology physician in Chicago, Illinois. Individual provider, active in the CMS NPPES registry since June 26, 2013.
## Identity
- **NPI:** 1538509294 (Entity type: Individual)
- **Enumerated:** June 26, 2013
- **Primary specialty:** Surgery - Surgical Oncology · taxonomy 2086X0206X
- **State license:** 036165097 (Illinois)
- **Sole proprietor:** No
## Practice location
- **Address:** 675 N SAINT CLAIR ST STE 21-700, Chicago, IL 60611-5975
- **Phone:** (312) 695-0990 · **Fax:** (312) 695-1144
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** Northwestern Medical Faculty Foundation (NPI 1346235314, Carol Stream, IL), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Oregon Health Sciences University School Of Medicine, class of 2015
## Record status
- **NPPES last updated:** October 26, 2026
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Source: [NPI Profile](https://npiprofile.com/npi/1538509294) · Data from the CMS NPPES public registry.