Colonoscopy is an excellent area for quality improvement because it is high volume, has significant associated risk and expense, and there is evidence that variability in its performance affects outcomes. The best end point for validation of quality metrics in colonoscopy is colorectal cancer incidence and mortality, but a more readily accessible metric is the adenoma detection rate. Fourteen quality metrics were proposed in 2006, and these are described in this article. Implementation of quality improvement initiatives involves rapid assessments and changes on an iterative basis, and can be done at the individual, group, or facility level.