We aimed to test the reliability of a developed questionnaire that measures and predict aversive endoscopic experience. Two questionnaires (pre- and postprocedure) were given to patients presenting for routine endoscopy. The first questionnaire elicited demographics, prior endoscopic experience, history of drug or alcohol use, patient expectations, and levels of anxiety and nervousness before procedure. After endoscopy, tolerance and willingness to repeat the examination were determined. The primary outcome of "adverse endoscopic experience" (AEE) was defined as a score of > or =5 on the postprocedure overall level of satisfaction or unwillingness to repeat endoscopy. Thirteen of 148 subjects reported an AEE. Items measuring the primary outcome were internally validated by reliability analysis which significantly correlated with measures of aversive experience like pain, nervousness, and suffering during the procedure. Preprocedure factors that were associated with AEE in the univariate analysis and multivariate analysis were nervousness (P = 0.02) and chronic use of psychotropic drugs or alcohol (P = 0.03). In conclusion, we have developed a questionnaire that reliably measures aversive endoscopic experience. Nervousness before procedure and chronic use of psychotropic drugs are reliable predictors of such experience.