A new benzodiazepine derivative, Rohypnol (Ro 5-4200), was used for management of general anesthesia with nitrous oxide, narcotics and muscle relaxants to evaluate the effect on the cardiovascular and respiratory system in 35 surgical patients. In each patient, we observed the blood pressure, pulse rate, minute volume and arterial blood gas analysis and also local effects, postoperative recovery state and amnesia. The results are as follows; 1) Induction dosage of Rohypnol was not constant as other benzodiazepines. 2) Rohypnol showed a little effect an the cardiovascular system. 3) The effects of Rohypnol on the respiratory system were negligible but slight depression was seen. 4) If respiration became shallower or apnea occured during induction with Rohypnol, it was preferred to use assisted or controlled ventilation with 100% oxygen. 5) It was thought better to give oxygen through a nasal catheter for prevention of decreased PaO2 in recovery room. 6) When we used the non-depolarizing muscular relaxants instead of S.C.C. for intubation, we observed that a significantly decreased amount of relaxant was needed for maintenance of general anesthesia.