In this study, we evaluated the effects of fentanyl, midazolam, and fentanyl-midazolam on cardiovascular system and blood glucose during endotracheal intubation in forty normotensive patients scheduled for elective surgery under general anesthesia. The patients were randomly classified into four groups; Group I (control) received tracheal intubation with thiopental 5 mg/kg (n=10), group II received tracheal intubation with fentanyl 6 ug/kg followed by thiopental 2 mg/ kg (n=10), group III received tracheal intubation with midazolam 0.3 mg/kg (n=10), group IV received tracheal intubation with fentanyl 4 ug/kg followed by midazolam 1 mg/kg (n=10). The changes of systolic blood pressure, diastolic blood pressure, mean arterial blood pressurie, heart rate, and blood glucose were compared in each group. The results were as follows; 1) In group I, endotracheal intubation caused a significant rise in SBP, HR and blood glucose. 2) In group II, endotracheal intubation caused little changes in SBP, DBP,MAP and blood glucose but HR was rised. 3) In group III, endotracheal intubation caused little changes in SBP, DBP, MAP, HR and blood glucose. 4) In group IV, endotracheal intubation caused little changes in SBP, DBP, MAP, HR and blood glucose.