In 31 adult patients who had undergone spinal or epidural anesthesia, we evaluated the effect of flumazenil in reversing midazolam, flunitrazepam or diazepam. The patients received midazolam 5 mg, flunitrazepam 1 mg or diazepam 5 mg 15 min after the spinal or epidural anesthesia. After the completion of operation, flumazenil (0.2 mg-1.0 mg) was administered until the patient became awake. Blood pressure, pulse rate and respiratory rate before and after administration of flumazenil showed no statistically significant changes in these groups. There were no significant differences in necessary amount of flumazenil among these groups. The time necessary for the patient to be awake in midazolam group was significantly shorter than that in flunitrazepam or diazepam group. Half of the patients in flunitrazepam and diazepam groups slept again after leaving the operating room, but they presented no clinical problems. In conclusion, we consider that flumazenil does not affect circulation and respiration, so it seems to be safe and effective for reversing benzodiazepins in clinical situation.