Objective To analyze the risk factors for the most common adverse events, i.e. abdominal pain and distension in sedation‑free colonoscopy. Methods This was a multicenter clinical study, in which clinical data of patients including outpatients and inpatients who underwent selective sedation‑free colonoscopy at six gastrointestinal endoscopy centers from July 2017 to December 2019 were collected, including patients'' general information, complicating diseases, examination time, examination results, and occurrence of adverse events of abdominal pain and distension. Univariate and multivariate logistic regression was performed to analyze the risk factors for adverse events of abdominal pain and distension during sedation‑free colonoscopy. Results A total of 2 394 patients underwent sedation‑free colonoscopy, among whom 690 (28.8%) suffered from abdominal pain, and 1 151 (48.1%) experienced abdominal distension. The results of multivariate logistic analysis showed that overweight (OR=1.33, 95%CI:1.09‑1.62, P=0.005), obesity (OR=1.55, 95%CI:1.14‑2.11, P=0.005) and combination of hypertension (OR=1.58, 95%CI:1.23‑2.02, P<0.001) were independent risk factors for abdominal pain during sedation‑free colonoscopy, and overweight (OR=1.40, 95%CI:1.17‑1.68, P<0.001) and combination of hypertension (OR=1.39,95%CI:1.10‑1.76, P=0.006) were independent risk factors for abdominal distension during sedation‑free colonoscopy. Conclusion Obesity, overweight and combination of hypertension are independent risk factors for abdominal pain, and overweight and combination of hypertension are independent risk factors for abdominal distension during sedation‑free colonoscopy.