The effects of fentanyl pretreatment on controlling the hemodynamic changes during induc- tion have been compared in 58 adult normotensive patients undergoing elective operation. Two groups of 29 patients were observed. Patients were randomly assigned to receive thiopental 5 mg/kg alone(control group) or fentanyl 8 ug/kg pretreatment with thiopental 3 mg/kg (fentanyl group) for induction of anesthesia. The changes of mean arterial pressure(MAP), heart rate(HR), peak flow index(PFI), ejection Fraction(EF), end diastolic index(EDI), cardiac indx(CI) and stroke index(SI) were checked and compared with preinduction control values. The results were compared between two groups. The results were as follows. MAP and HR 1 minute after intubation increased significantly compared with preinduction values(p<0.001) in control group but showed minimal changes in the fentanyl group. The changes of PFI, EF, EDI, CI and SI showed decreasing tendencies after 30 seconds of thiopental injection in both groups, but the changes were small in the fentanyl group. Sinus tachycardia, premature ventricu1ar contraction, bigeminy were observed in both groups but the incidences were very low in the fentanyl group. It is suggested from the above results that fentanyl pretreatment(8ug/kg) reduces the hemo- dynamic changes during induction of general anesthesia and is more safe method for induction of cardiac or cerebrovascular disease patients.