About Jason Haas, D.O.

Board Certified Gastroenterologist

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Jason Haas, D.O.

Jason Haas, D.O. is dedicated to providing the highest quality of care to all his patients.  He has strong communication skills which allow him to connect with patients, staff and colleagues. 


For the past eight years, Dr. Haas has been a gastroenterologist practicing in Springfield, Missouri with Cox Medical Clinic.  He is a board-certified gastroenterologist that completed his GI Fellowship training at Aurora Health Care in Milwaukee, WI and his Internal Medicine Residency at Gundersen Health Care in LaCrosse, WI.  


His wife is from. St. Louis, and in their spare time Dr. Haas enjoys traveling with her and their two daughters.  Dr. Haas has been a member of the Colorectal Awareness Party in Springfield, which helps raise money and provide free colonoscopy evaluations for patients in need.

Gateway Gastroenterology

Main Office – Chesterfield:
121 Saint Luke’s Center Drive, Suite 406, Building A
Chesterfield, MO 63017
Phone: 314-529-4900 | Fax: 314-434-2679 | After-Hours Exchange: 855-224-7875

Gateway Endoscopy Center: 314-336-1130
St. Luke’s Hospital – GI Lab (East Medical Building): 314-542-4863
St. Louis Multispecialty Surgery Center: 636-779-0079