The present invention relates to a washing machine and a method of controlling the washing machine. According to a washing machine and a method of controlling the washing machine in accordance with the present invention, a drum operates at a first speed so that part of the laundry tumbles within the drum and another part of the laundry adheres to the drum. The laundry amount within the drum is sensed during the first speed operation. Operation commands for driving the drum after the first speed operation are changed based on the sensed laundry amount. Accordingly, at the time of the dehydration cycle, stability of the washing machine and laundry balancing can be ensured.