Background: Colonoscopy is a common diagnostic and therapeutic method for assessing the lower gastrointestinal system. This study aimed to compare the differences between water immersion, water exchange and air insufflation colonoscopy under good bowel preparation conditions. Subjects and methods: Randomized controlled trial study was conducted in 30 patients who performed a colonoscopy between January 2023 to July 2023 in internal medicine department, hepato- gasterontrology unit at Zagazig University Hospitals, equally divided into three groups; Group A: Air insufflation who were submitted to traditional method with minimal insufflation, with warm water used to wash residual stool. Group 2: Water immersion who were submitted to infusion with clean water to improve the visibility of the intestinal lumen. Group 3: Water exchange participants were subjected to infusion using an insertion strategy that included gasless insertion to the cecum, maximizing cleanliness during insertion, and preventing colon distension through excess water removal and residual air preparation. Results: there was no statistical significant difference regarding use of anesthetic drugs or time of procedure. Regarding result of colonoscopy (internal piles was the most prevalent result; 40%, 40% and 70% within air insufflation, water immersion and water exchange groups). Regarding cecal intubation time; difference is significant between air insufflation and water immersion group where time is significantly higher in air insufflation group as compared to water immersion group) p≤0.001. Conclusion: Water exchange colonoscopy is superior to Water immersion, in reducing insertion pain, and cecal intubation time, minimizing sedation requirements .