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

Gretta Mae Colby, MD

Individual provider Internal Medicine Physician · NPI 1306587639

Gretta Mae Colby, MD is an Internal Medicine in Milwaukee, Wisconsin. Graduated from Medical College of Wisconsin in 2022, 4 years ago. Practices with Aurora Medical Group, Inc, a 3,741-clinician group and accepts Medicare assignment. Licensed in Wisconsin.

Years since qualifying
4
Trained at
Medical College of Wisconsin
Licensed in
WI
In the registry since
2022
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

945 N 12th St
Milwaukee, WI 53233-1305
Phone: (414) 219-7427
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 83738-20 (WI)

Record details

NPI number1306587639
Entity typeIndividual (Type 1)
GenderFemale
Credentials MD
Sole proprietorYes
NPI enumeratedApril 1, 2022
Last updated in NPPESSeptember 18, 2025
Certification dateSeptember 18, 2025
Mailing address945 N 12th St, Milwaukee, WI 53233-1305

Medicare enrollment

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

Medicare specialtyINTERNAL MEDICINE
Medical schoolMEDICAL COLLEGE OF WISCONSIN
Graduated 2022 (4 years in practice)
Group practice Aurora Medical Group, Inc. — 3741 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

Other providers in Milwaukee