A washing machine including a washing tub to allow enhancement in washing efficiency. A washing tub of the washing machine includes a pattern having a protrusion portion to generate friction force between laundry and the washing tub and to thereby increase washing efficiency. The pattern has a concave-convex structure and performs action similar to a lifter, washing efficiency may be enhanced using tumbling generated by the pattern. A plurality of drain holes are arranged in a certain pattern in the washing tub to prevent a dehydration bottleneck phenomenon in which dehydration is concentrated at a particular drain hole and to increase a dehydration rate. The pattern is provided such that protrusion portions and recessed portions continue on the surface of the washing tub to enhance stiffness of the washing tub.