OBJECTIVES: High-quality bowel preparation is crucial for achieving the goals of colonoscopy. However, choosing a bowel preparation in clinical practice can be a challenge because of the many formulations. This study aims to assess the association between bowel preparation type and detection of advanced adenoma during colonoscopy examination in a community setting. METHODS: A retrospective, observational study was conducted utilizing a colonoscopy screening/surveillance database in central Illinois during the period of January 1, 2010 to March 31, 2014. Patients without bowel preparation assessment were excluded from this study. Controlling for the confounders, generalized linear models were used to estimate the adjusted impact [odds ratio (OR)] of bowel preparation type on the quality of preparation (excellent, good, fair and poor), and on the detection of advanced adenoma. RESULTS: A total of 28,368 colonoscopies, half were male and the average age was 61±9 years. The majority (70.2%) of bowel preparations used polyethylene glycol (PEG), followed by sodium sulfate (21.4%), sodium phosphate (2.5%), magnesium sulfate (0.4%) and others. Compared to PEG, magnesium sulfate had a poorer quality of bowel preparations (OR=0.6, 95% CI 0.4-0.9; p<0.05), whereas the quality of bowel preparation was significantly improved by using sodium sulfate (OR=5.7, 95% CI 5.4-6.1; p<0.001), and sodium phosphate (OR=2.1, 95% CI 1.8-2.5; p<0.001). For those who had adequate bowel preparation, the better quality of preparation significantly increased the detection rate of advanced adenoma (5.0%, 3.6% and 2.9% for Excellent, Good and Fair, respectively). Sodium sulfate had a higher detection rate of advanced adenoma than PEG (4.8% versus 3.7%, p<0.001). CONCLUSIONS: Sodium sulfate based preparations should be recommended in the community setting for colonoscopy when available because their high quality preparations increase the detection of advanced adenoma.