Sedation-free colonoscopy in the US is feasibility. We conducted a prospective IRB-approved trial in patients willing to begin without sedation. Two thousand ninety-one consecutive patients were eligible. Our data reveal that sedation on demand colonoscopy was successful in 99.2% of all patients; 99.3%, 99.4% and 99.1% of those medicated at start of colonoscopy; unsedated throughout; and medicated during colonoscopy, respectively. There was a reduction in complications, 0.43% vs. 6.67%, unsedated versus sedated. Ninety-seven point five percent of unsedated patients were willing to repeat without sedation. The adenoma detection rate was 32% in men and 22% in women. Thus, unsedated colonoscopy is possible in a large percentage of patients, particularly if the patient had previous colostomy or left hemicolectomy. Patients who present for their procedure without a driver and patients in whom the completeness of the bowel preparation was uncertain are good candidates to start unsedated as are patients who have had previous unsedated examination.