The aim of this study was to compare the effects of 3 different sedative-analgesic regimens in patients with intracranial mass lesions undergoing stereotactic brain biopsy. A 135 outpatients with American Society of Anesthesiologists I to II were divided into 3 groups: group A (n=45) received a loading dose of IV alfentanil 7.5 μg/kg followed by infusion rate of 0.25 μg/kg/min; group F (n=45) received a bolus dose of 1 μg/kg IV fentanyl and repeated as needed; and group R (n=45) received infusion of 0.05 μg/kg/min remifentanil. Target level of sedation was 3 to 4 of the Ramsay Sedation Scale. Systolic and diastolic blood pressure, heart rate, respiratory rate, peripheric oxygen saturation (SpO2), and end-tidal carbon dioxide were recorded at different stages of the procedures. The patients in group F had significantly lower mean heart rate than those in groups A and R, but this was not in the limits of the bradycardia. The patients in group A had significantly lower mean SpO2 than those in the other groups, but mean SpO2 values did not drop below 94%. There were no significant differences in end-tidal carbon dioxide and respiratory rate values among the groups. Our results suggest that all 3 regimens have relatively similar hemodynamic and respiratory responses. The use of bolus fentanyl technique caused less hemodynamic stability. The continuous infusion technique of remifentanil or alfentanil provided better control on hemodynamic parameters.