A method of controlling a washing machine, capable of detecting clothes contained in the washing machine by rotating a drum. The method includes supplying a predetermined amount of water when a barrel cleaning is executed, soaking an interior of a drum in water, draining water after the interior of the drum has been soaked in the water, and detecting clothes contained in the drum by rotating the drum. Whether to perform a barrel cleaning is determined according to the existence of the clothes in the drum, so that vibration and noise are prevented from being generated in the washing machine, and accident due to the movement of the washing machine is prevented.