A washing machine including an auxiliary washing tub in a washing tub, and a method for controlling the same are disclosed. The washing machine includes a main washing tub and an auxiliary washing tub through which different laundry can be classified according to the weight or category of laundry such that the classified laundry can be separately washed. As a result, user convenience increases, and the entire washing time and unnecessary energy consumption can be reduced. When the main washing tub and the auxiliary washing tub are simultaneously operated, when only the main washing tub is independently operated, or when only the auxiliary washing tub is independently operated, laundry can be effectively washed in different ways in the washing tub and the auxiliary washing tub according to an optimum washing algorithm achieved by a combination of washing-tub rotation and pulsator rotation, such that laundry can be less damaged and washing performance can be improved.