Background and aim Whole-colon water exchange (WWE) reduces insertion pain, increases cecal intubation success and adenoma detection rate, but requires longer insertion time, compared to air insuffiation (AI) colonoscopy.Whether water exchange limited to the left colon (LWE) can speed up insertion with equivalent results is unknown.The aim of our study is to compare cecal intubation time and other pertinent outcomes of WWE, LWE and AI colonoscopy.