High quality colonoscopy must be secured Colonoscopy plays a key role in the work-up of digestive diseases and constitutes the cornerstone in colorectal cancer diagnosis and prevention. Data suggest that the quality of colonoscopy varies widely between different endoscopists. This article summarizes current evidence and expert consensus on quality indicators, along with the evidence supporting their use in benchmarking, quality reporting, and continuous quality improvement in order to secure high quality colonoscopy. In particular, four quality indicators, i.e. adenoma detection rate, compliance with guidelines on intervals for endoscopic surveillance, cecal intubation rate and complications, should be monitored in endoscopy units to ensure that colonoscopy practice is of high quality. Proper performance and documentation of high quality colonoscopy is critical for reducing colorectal cancer incidence and mortality.