Robert McMahon MD 

Colonoscopy Doctor

Call Us:  1 (314) 492-4100

Dr Robert McMahon is Board Certified by the American Board of Internal Medicine in both Gastroenterology and Internal Medicine.  He is a MD graduate of Washington University School of Medicine in St Louis and completed internship and residency there (Barnes-Jewish Hospital).  

After completing his Gastroenterology Fellowship at University of Arkansas for Medical Sciences in Little Rock, he remained in private practice in Little Rock for several years before returning to St Louis.  He has continuously practiced gastroenterology in St Louis since then.  He is past President of the St Louis Metropolitan Medical Society and a Fellow of the American College of Gastroenterology (FACG).

Virtually all insurance plans and Medicare are accepted.  Dr. McMahon has privileges at several hospitals and surgery centers.  He performs colonoscopy screening as well as diagnostic and therapeutic colonoscopies.  He also does upper endoscopy procedures.


Dr. McMahon is committed to providing the highest quality care and personal attention based on experience and education.  We strive for promptness, courtesy and convenience.


Robert McMahon MD in St Louis has a  mission to provide personalized, high-quality care on an as-needed or preventative basis.  We have created a practice that we believe in and choose for our own family members.



Screening colonoscopy saves lives!  

A colonoscopy doctor like Dr. McMahon can help you prevent colon cancer.


To schedule an appointment for procedure, please call:  (314) 492-4100. 

CLOSED TO NEW PATIENTS - PRIOR OR EXISTING PATIENTS ONLY - NO OFFICE VISITS