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

Mark T Duffy, MD

Individual provider Ophthalmology Physician · NPI 1235167537

Mark T Duffy, MD is an Ophthalmology in Green Bay, Wisconsin. Graduated from University of Illinois College of Med (CHI/PEOR/ROCK/Chm-Urb) in 1992, 34 years ago. Practices with Baycare Clinic LLP, a 196-clinician group and accepts Medicare assignment. Licensed in Wisconsin.

Years since qualifying
34
Trained at
University of Illinois College of Med (CHI/PEOR/ROCK/Chm-Urb)
Licensed in
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.

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Practice location Address checks out

2253 W Mason St
Green Bay, WI 54303-4706
Phone: (920) 327-7000
Fax: (920) 327-7005
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Ophthalmic Plastic and Reconstructive Surgery Physician (primary) Taxonomy 207WX0200X · Licence 47208 (WI)
Ophthalmology Physician Taxonomy 207W00000X · Licence 47208 (WI)

Record details

NPI number1235167537
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJune 28, 2006
Last updated in NPPESApril 21, 2026
Certification dateApril 21, 2026
Mailing address1035 Kepler Dr, Green Bay, WI 54311-8320

Medicare enrollment

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

Medicare specialtyOPHTHALMOLOGY
Medical schoolUNIVERSITY OF ILLINOIS COLLEGE OF MED (CHI/PEOR/ROCK/CHM-URB)
Graduated 1992 (34 years in practice)
Group practice Baycare Clinic Llp — 196 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

Other providers in Green Bay