An apparatus and method for reducing power consumption of a portable terminal are provided. More particularly, an apparatus and method for reducing power consumption generated in an idle state in order to solve a power consumption problem in a portable terminal are provided. The apparatus includes a stale determination unit which is configured independently from an application processor for controlling applications and which wakes up when entering an idle mode to allow the application processor to sleep, and thereafter determines a state of the portable terminal, and if it is determined that the portable terminal escapes from the idle mode, allows the application processor to wake up.