Abstract Introduction Following incomplete colonoscopy (IC) it is reported that there is up to five-fold increased risk of colorectal cancer. Our aim was to determine the final clinical outcome for patients with a prior IC. Method A multi-centre retrospective observational study involving three endoscopy units. All consecutive patients having colonoscopy from over 18 months were analysed. Exclusion criteria included IC was due to obstructing cancer, follow up was not performed due to non-attendance at clinic or investigation and incomplete data set. Electronic notes were analysed to determine patient’s final clinical outcome. All patients were followed up for minimum of six months. Results Of the 8,490 colonoscopies, 733 (8.6%) were IC. 86 (11.7%) were excluded. Of the 647 included, 469 (72.4%) were females and 473 (73.1%) has further colonic investigations. Secondary investigations were: CT colonography 169 (35.7%), repeat colonoscopy 161 (34.0%), barium enema 95 (20.1%) and others 48 (10.1%). The repeat colonoscopy group achieved a complete colonoscopy in 111 (68.9%) patients. For those who had further investigations 15 (3.2%) had colorectal cancer and 12 (2.5%) has polyps ≥1cm. Conclusions There is significant risk of missing colorectal malignancy and large polyps following IC. Further colonic investigations should be carried out in this cohort of patients.