This study was undertken to estimate the induction time, hemodynamic responses and local venous complications after intravenous administration of the midazolam, the water-soluble benzodiazepine derivative, comparing with those of the thipental, as an induction agent. Sixty ASA Class I or II surgical patients were divided into two groups: I and II, and were given 5 mg/kg thiopental sodium and 0.15 mg/kg midazolam hydrochloride, respectively. The results obtained were as follows; 1) The induction timeQoss of palpebral reflex) of the group II(88.7±41.8 seconds)was longer than those of the group I (19.5±3.7 seeonds). 2) The magnitude of fall in the systolic blood presure, 1 and 2 minute after intravenous administration of the induction agents observed in the group II was smaller than those observed in the group I compared with the pre-induction valuea But other parameters did not change significantly compsred with the pre-induction values in both groups. 3) In five patients of the group I, they complained of pain on the injection, but no patient of the group II complained of it. There was no statistically significant difference in the incidence of the postoperative local venous complications on the injection sites such as thrombosis or phlebitis between both groups.