We examined a number of patient variables, including three different scales of preprocedure patient anxiety, to determine which best predicted patient cooperation and satisfaction with gastrointestinal endoscopy. We prospectively evaluated 251 patients undergoing outpatient diagnostic esophagogastroduodenoscopy and colonoscopy under conscious sedation. All were given a questionnaire on arrival to our endoscopy center that included three measures of preprocedure anxiety: (a) a single question asking how anxious the patient was (termed "Anxiety I" scale); (b) a visual linear analog scale of anxiety; and (c) the Hospital Anxiety and Depression scale. Patient cooperation during the procedure was rated by the attending endoscopist. Patients were telephoned the next day to complete a questionnaire assessing their endoscopic experience. Logistic regression analysis was used to construct models for predicting which patients were most likely to have difficulty during their procedures from both the endoscopists' and the patients' standpoint. Statistical analysis identified three parameters that by themselves significantly correlated with patient cooperation during endoscopy: age (p = 0.008), Anxiety I scale (p = 0.03), and visual linear analog anxiety score (p = 0.02). When used together, age, type of procedure, and Anxiety I scale were the best predictors of patient cooperation from the standpoint of the endoscopist. Age, type of procedure, Anxiety I scale, and education level were the best predictors of satisfaction with endoscopy from the perspective of the patient. Good cooperation during endoscopy was associated with greater patient satisfaction.