Midazolam 0.1 mg/kg was compared with diazepam 0.15 mg/kg intravenously in patients undergoing gastroscopy. The patients receiving midazolam were more sedated at the end of the procedure. The mean discharge times from the clinic for diazepam and midazolam patients were 85 and 102 minutes, respectively. The principal differences between the two drugs were that midazolam had a faster rate of onset, was virtually free from venous complications, provided much better amnesia (90% compared with 50%), and although the recovery time was longer with midazolam, the rate of recovery during the period of observation was faster. Neither drug caused any significant cardiorespiratory depression.