A broadcast receiver which outputs a warning signal when the amount of remaining battery power is insufficient to perform a scheduled operation of a broadcast program, and a method of controlling an operation of the broadcast receiver, are discussed. According to an embodiment, the method includes identifying broadcast information of a predetermined broadcast program; detecting an amount of remaining power of a battery of the broadcast receiver; determining if the remaining battery power is sufficient to perform a scheduled operation for the predetermined broadcast program based on the broadcast information and the detected remaining battery power; and outputting a warning signal if the determining determines that the remaining battery power is insufficient to perform the scheduled operation.