Dr. Kevin Sieja was born and raised in Chicago, Illinois. For his undergraduate studies, he attended the University of Notre Dame, graduating summa cum laude. He received his medical degree from Northwestern University where he was elected to Alpha Omega Alpha honors society. Dr. Sieja then completed his internal medicine residency and fellowship in gastroenterology at the University of Colorado Health Sciences Center. During fellowship, his research interests in disorders of the liver and intestine led to multiple publications. He is actively involved in clinical research and teaching. Dr. Sieja mentors residents from the University of Colorado. He specializes in all disorders of the digestive system and liver. Dr. Sieja is Board Certified in both Internal Medicine and Gastroenterology and is a member of the American Gastroenterological Association, the American College of Gastroenterology and the American Society of Gastrointestinal Endoscopy.

Dr. Sieja’s wife, Amber, is an internal medicine physician in Denver. They enjoy the outdoors and spending time with their three children.


Medical School
Northwestern University

University of Colorado Health Sciences Center

University of Colorado Health Sciences Center

Certifications & Memberships

Board Certified in Internal Medicine and Gastroenterology




Internal Medicine

Office Locations

Colorado Gastroenterology
8155 E 1st Ave
Denver, CO 80230
Phone: (303) 861-0808