The advent of capsule endoscopy has revolutionized evaluation of the small bowel. Capsule endoscopy has become the criterion standard as the initial examination to diagnose small-bowel abnormalities, but does not allow for tissue sampling or therapeutic intervention. Deep enteroscopy can be performed by using a balloon-assisted device or a spiral overtube for both diagnostic and therapeutic interventions of the small bowel. Deep enteroscopy is time-consuming and requires special endoscopes and accessories to perform the examination. We studied a novel through-the-scope balloon catheter system used for deep enteroscopy that uses a conventional colonoscope and standard accessories.