The present invention relates to an ODT control circuit which is controlled in synchronization with an external clock during power-down mode. An ODT control circuit according to the present invention includes a clock control circuit which receives a synchronized internal clock signal and a DLL clock signal, and selects either one of the internal clock signal or the DLL clock signal according to the power mode to output a plurality of delayed clock signals; and an ODT control signal generation circuit which receives an ODT command, and controls the ODT command with the internal clock signal and a plurality of the delayed clock signals to generate and output an ODT control signal. According to the present invention, an ODT control signal for controlling an on-die termination resistor is synchronized with an external clock even during power-down mode, thereby more effectively controlling the ODT control signal.