Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.

Theresa K Hayssen, MD

Individual provider Colon & Rectal Surgery Physician · NPI 1265412365

Theresa K Hayssen, MD is a General Surgery in Brookfield, Wisconsin. Graduated from Southern Illinois University School of Medicine in 1992, 34 years ago. Practices with Ascension Medical Group-Southeast Wisconsin Inc, a 555-clinician group and accepts Medicare assignment. Licensed in Wisconsin.

Years since qualifying
34
Trained at
Southern Illinois University School of Medicine
Licensed in
WI
In the registry since
2006
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

17000 W North Ave Ste 107W
Brookfield, WI 53005-4423
Phone: (262) 786-3722
Fax: (262) 786-0116
Show map & directions

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

Specialties & licences

Colon & Rectal Surgery Physician (primary) Taxonomy 208C00000X · Licence 39624 (WI)

Record details

NPI number1265412365
Entity typeIndividual (Type 1)
GenderFemale
Credentials MD
Sole proprietorNo
NPI enumeratedJanuary 17, 2006
Last updated in NPPESFebruary 10, 2015

Medicare enrollment

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

Medicare specialtyGENERAL SURGERY
Medical schoolSOUTHERN ILLINOIS UNIVERSITY SCHOOL OF MEDICINE
Graduated 1992 (34 years in practice)
Group practice Ascension Medical Group-Southeast Wisconsin Inc — 555 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations9 on file with Medicare

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