Comparison of the ease of upper endoscopy, patient tolerance, and amnestic effect, using diazepam, midazolam, or no sedation, was performed on 149 patients. Midazolam and diazepam sedation produced better conditions and improved patient acceptability. Midazolam was associated with better patient tolerance, less thrombophlebitis, and more amnesia than diazepam, but shared a similar recovery time. Midazolam should replace diazepam as the drug of choice in those patients requiring sedation for upper endoscopy.