Objective: This study aimed to compare the cost-effectiveness of low-flow (1 liter per minute (LPM)) and medium-flow (2 LPM) anesthesia. Material and Methods: Seventy patients aged 18–60 years who were undergoing elective surgery under general anesthesia were randomly allocated to receive a total gas flow rate of 1 LPM (group 1) and 2 LPM (group 2) during the maintenance of anesthesia. The primary outcome was to compare the cost and consumption of sevoflurane and litholyme. The secondary outcomes were hemodynamic stability and time to extubation. Results: The cost and consumption of sevoflurane in group 1 (197.3 Thai Bahts (THB)/hour (hr) and 9.6 milliliter (ml)/ hr) were significantly less than those in group 2 (303.2 THB/hr and 14.8 ml/hr; p-value<0.001). Although there was no difference in the cost and consumption of litholyme between the two groups, the summary cost of sevoflurane and litholyme in group 1 (237.7 THB/hr) was significantly less than that in group 2 (339.6 THB/hr; p-value<0.001). The mean arterial pressure, heart rate, and time to extubation were not significantly different in both groups. Conclusion: Patients undergoing elective surgery under general anesthesia with a total flow of 1 LPM can save on the cost of sevoflurane and litholyme, which is equivalent to 101.9 THB/hr.