An apparatus controls battery power in a mobile terminal supporting digital multimedia broadcasting (DMB) service. In the apparatus, first and second radio frequency (RF) signal processors respectively process DMB signals and call signals received through associated antennas. A DMB modem demodulates DMB signals output from the first RF signal processor. A voltage detector detects a voltage of the mobile terminal and disables the DMB modem if the detected voltage is less than or equal to a threshold.