BACKGROUND AND STUDY AIMS: Sedation and monitoring practice during colonoscopy varies between centers and over time. Knowledge of current practice is needed to ensure quality of care and help focus future research. The objective of this study was to examine sedation and monitoring practice in endoscopy centers internationally. PATIENTS AND METHODS: This observational study included consecutive patients referred for colonoscopy at 21 centers in 11 countries. Endoscopists reported sedation and monitoring practice, using a standard questionnaire for each patient. RESULTS: 6004 patients were included in this study, of whom 53 % received conscious/moderate sedation during colonoscopy, 30 % received deep sedation, and 17 % received no sedation. Sedation agents most commonly used were midazolam (47 %) and opioids (33 %). Pulse oximetry was done during colonoscopy in 77 % of patients, blood pressure monitoring in 34 %, and electrocardiography in 24 %. Pulse oximetry was most commonly used for moderately sedated patients, while blood pressure monitoring and electrocardiography were used predominantly for deeply sedated patients. Sedation and monitoring use ranged from 0 % to 100 % between centers. Oxygen desaturation (LT /= 85 %) occurred in 5 % of patients, of whom 80 % were moderately sedated. On average, three staff members were involved in procedures. An anesthesiologist was present during 27 % of colonoscopies, and during 85 % of colonoscopies using deep sedation. CONCLUSIONS: Internationally, sedation and monitoring practice during colonoscopy varied widely. Moderate sedation was the most common sedation method used and electronic monitoring was used in three-quarters of patients. Deep sedation tended to be more resource-intensive, implying a greater use of staff and monitoring.