Thermal preference of free-living yellow-margined box turtle, Cuora flavomarginata, was studied in a mesic forested habitat using a combination of radiotransmitters and temperature dataloggers attached to individual turtles. Patterns of mean weekly shell surface temperature variation of selected individuals were highly related to seasonal change of environmental temperature, with a peak temperature of 24.5-25.1 • C in males and 26.0-27.0 • C in females during June and July. Minimum shell surface temperature occurred in late January (4.5-7.6 • C). Despite a small sample size, there were significantly intersexual differences in mean weekly shell surface temperature during nesting season. Individual females of C. flavomarginata tended to maintain higher shell surface temperature during nesting season (May-July). This difference was mostly pronounced during the day. There were no obviously intersexual differences prior to and after nesting season. Our results do not support the previous predictions that gravid C. flavomarginata may select higher environmental temperatures prior to nesting season.