Background: The changes in the hemodynamic parameters when the patients assumed a prone position from a supine position were examined using the FloTrac/EV1000TM system, during general anesthesia. Methods: A total of 56 adult patients with American Society of Anesthesiologists physical status I-II and undergoing elective lumbar spine surgery were enrolled in the study. The hemodynamic parameters, such as the mean arterial pressure, heart rate, cardiac index, stroke volume variation, systemic vascular resistance index, central venous pressure, and peak airway pressure, were recorded when the patients were in a supine position and then in a prone position. Results: No significant differences were found in the subjects’ hemodynamic parameters between when the subjects were in a supine position and when they were in a prone position, except in the central venous pressure and peak airway pressure, both of which were elevated when the subjects were in a prone position. Conclusions: There were no differences in hemodynamic parameters between supine and prone positions measured by FloTrac/EV1000TM system during general anesthesia.