Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

William B Seiden, MD

Individual provider Internal Medicine Physician · NPI 1407915978

William B Seiden, MD practises Internal Medicine in Lake Forest, Illinois. Graduated from University of Illinois College of Med (CHI/PEOR/ROCK/Chm-Urb) in 1990, 36 years ago. Practices with Northwestern Medical Faculty Foundation, a 4,394-clinician group, accepts Medicare assignment and offers telehealth. Licensed in Illinois and Wisconsin.

Years since qualifying
36
Trained at
University of Illinois College of Med (CHI/PEOR/ROCK/Chm-Urb)
Licensed in
IL, WI
In the registry since
2006
Specialties on file
2
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

See every abbreviation used in this directory →

Claim this listing Report a problem Suggest an edit

Practice location Address checks out

800 N Westmoreland Rd Ste 201
Lake Forest, IL 60045-1687
Phone: (608) 242-6850
Show map & directions

Directions in Google Maps · Apple Maps · OpenStreetMap

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Internal Medicine Physician (primary) Taxonomy 207R00000X · Licence 63951 (WI)
Internal Medicine Physician Taxonomy 207R00000X · Licence 036086127 (IL)

Record details

NPI number1407915978
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedDecember 8, 2006
Last updated in NPPESJuly 21, 2022

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyINTERNAL MEDICINE
Medical schoolUNIVERSITY OF ILLINOIS COLLEGE OF MED (CHI/PEOR/ROCK/CHM-URB)
Graduated 1990 (36 years in practice)
Group practice Northwestern Medical Faculty Foundation — 4394 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients280
Services billed 1,787 a service is one billed item, such as a visit, a test or a procedure
Average patient age76

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician. Those with a page here are linked.

Colleagues at Northwestern Medical Faculty Foundation

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 4394 clinicians in the practice; 12 are shown here.

Other providers in Lake Forest