['Interest in effective ways to complete colon examinations in patients who had previously undergone failed colonoscopies has increased recently.', 'To determine whether water immersion decreased the need for ancillary equipment to achieve cecal intubation in patients who had previously undergone incomplete colonoscopies.', 'Retrospective cohort study.', 'Tertiary academic center.', 'A total of 345 consecutive patients referred to a tertiary center for the indication of a previous incomplete colonoscopy.', 'Colonoscopy with or without water immersion insertion.', 'Cecal intubation rates, type of equipment, and maneuvers used.', 'Cecal intubation was achieved in 332 of 345 patients (96.2%) and was similar in those with and without water immersion (170/178, 95.5% vs 162/167, 97%, P = .58). An external straightening device was used in 6 of 178 cases with water immersion (3.4%) compared with 25 of 168 cases with air insufflation (15%) (P < .0001). Among patients with a redundant colon as the sole cause of previously incomplete examinations, water immersion required an external straightener in 7% compared with 37% with air insufflation during insertion (P < .0001), and position change was required in 5% of those with water immersion compared with 22% with air insufflation (P = .01).'] Does water immersion simplify cecal intubation in patients with redundant colons and previous incomplete colonoscopies?