Background and study aims: Cecal intubation rate (CIR) and adenoma detection rate (ADR) have been found to be inversely associated with the occurrence of post-colonoscopy colorectal cancer. Depicting differences in CIR and ADR between hospitals could provide incentives for quality improvement. The aim of this study was to compare quality parameters of routine colonoscopies between seven hospitals in The Netherlands in order to determine the extent to which possible differences were attributable to procedural and institutional factors. Patients and methods: Consecutive patients undergoing colonoscopy were prospectively included between November 2012 and January 2013 at two academic and five nonacademic hospitals. Patients with inflammatory bowel disease or hereditary colorectal cancer syndromes were excluded. Main outcome measures were CIR and ADR. Results: A total of 3129 patients were included (mean age 59+/-15 years; 45.5% male). The majority of patients (86.2 %) had a Boston Bowel Preparation Scale (BBPS) score >= 6. Overall CIR was 94.8 %, ranging from 89.4% to 99.2% between hospitals. After adjustment for case mix (age, sex, American Society of Anesthesiologists score, and indication for colonoscopy), factors associated with CIR were hospital and a BBPS score >= 6. Overall ADR was 31.8% and varied between hospitals, ranging from 24.8% to 46.8 %. Independent predictors for ADR were hospital, BBPS score >= 6, and cecal intubation. By combining CIR and ADR for each hospital, a colonoscopy quality indicator (CQI) was developed, which can be used by hospitals to stimulate quality improvement. Conclusion: Differences in the quality of colonoscopy between hospitals can be demonstrated using CIR and ADR. As both indicators are affected by institution and bowel preparation, a comparison between hospitals based on the newly developed CQI could assist in further improving the quality of colonoscopy.