Abstract: A washing machine including a drum capable of improving washing efficiency is provided. The washing machine includes a body, a tub provided at an inside the body to store wash water, a drum rotatably provided at an inner side of the tub to accommodate laundry, a driving apparatus to rotate the drum, protrusions that are formed of polygons having polygonal shapes and protruding inward from the drum, and a through-hole provided between adjacent protrusions to drain water. A protrusion having polygons generates frictional force between laundry and the drum, thereby increasing the washing power. The through-holes are uniformly located around the protrusion, thereby preventing a spin dry water bottleneck phenomenon that occurs when water from a spin dry is concentrated on a certain through-hole, and thus enhancing the spin dry efficiency.