Midazolam is a new, water-soluble benzodiazepine that has been reported to produce a greater degree of amnesia than does diazepam. This study compares the amnesia produced in patients sedated with midazolam or diazepam or in combination with fentanyl during oral surgery. Twenty-four hours after surgery, each patient answered a questionnaire designed to assess his or her recall of events during and after surgery. Patients who received midazolam alone recalled significantly less than did patients in either diazepam group. The addition of fentanyl to midazolam did not produce any significant difference in recall.