Adequacy of bowel cleansing is a quality measure for colonoscopy, affecting both its safety and diagnostic accuracy. Among several bowel preparation quality scales referred to in literature, the Boston Bowel Preparation Scale (BBPS) is regarded as one of the most valid and reliable. However, BBPS is conditioned by a partially subjective appraisal. We report the results of a retrospective study that evaluated the quality of bowel preparation using BBPS and the factors associated with cleansing in routine clinical practice, in a series of consecutive examinations performed in a tertiary care hospital.