The technique of double balloon endoscopy developed for retrograde enteroscopy has been used to perform colonoscopy in patients with difficult progression of the endoscope. A new endoscopic system, the double balloon colonoscope (DBC) has recently been developed (EC-450B15 Fujinon Optical, Saitama, Japan). Aim of this study was to evaluate the ability of DBC to achieve a complete colonoscopy in patients in whom it previously failed in order to determine indications and refine technical stipulations. Patients and Method: Sixteen patients (11 women, 5 men, 66 ± 12 years) were included after an incomplete colonoscopy, excluding failures due to poor bowel cleansing. After cleansing with 2 × 2L PEG, colonoscopy was performed under general anaesthesia with propofol by an anaesthesiologist, with EC-450B15, a 182 cm long, thin colonoscope (diameter 9.4 mm), an operating channel of 2.8 mm and a view angle of 140°. The overtube is 101 cm long and 13.2 mm in diameter. The distal end of both the endoscope and the overtube are equipped with a latex balloon that can be inflated/deflated under control of a barostatic pump. Completeness of the colonoscopy was defined as the possibility to maintain the endoscope in a stable position in the caecum Indication, reason for failure of previous colonoscopy, time to reach the caecum, need for fluoroscopic control of the progression and adverse events were prospectively recorded. Results: Previous colonoscopy failed due to post-surgical adhesions in 9 cases, a dolichocolon with a long sigmoid or transverse loop in 6 and a fixed inflammatory sigmoid loop in one patient with Crohn's disease. Full colonoscopy was achieved in 15 out of 16 patients. Terminal ileum was examined in 12. The average time to reach the caecum was 16 ± 9 minutes. In 11 patients, the colonoscope was used with the overtube and the two balloons, inflated before pulling down the endoscope to straighten it when needed. In 5 patients, the colonoscope was used without overtube and reached the caecum in 4. In one case, the progression of the endoscope was limited to the splenic flexure because of a long sigmoid loop but a further attempt with the complete device allowed the caecum to be reached. Examinations were performed by one examiner with the help of a trained nurse. Fluoroscopy was used in 7 patients to monitor endoscope progression. No complication was reported. Conclusion: DBC enables full colonic examination in patients with previous difficult colonoscopy. The technique to be used -overtube or endoscope alone- depends on the reason why previous colonoscopy failed. Fluoroscopic assessment of the progression could further be limited with increasing experience.