A washing machine in which steam and hot water are supplied to heat wash water. The washing machine includes a water tub for containing wash water, a steam generating unit for heating water supplied thereto, thereby generating steam, a water supply unit for supplying water into the water tub and the steam generating unit, a steam supply unit for supplying the steam generated from the steam generating unit into the water tub, and a hot water supply unit for supplying hot water from the steam generating unit into the water tub. In the washing machine, the temperature of wash water can be rapidly increased in accordance with steam and hot water supplied into the water tub. Accordingly, it is possible to reduce the overall wash time while reducing the amount of wash water to be used. The energy consumed to heat the wash water can also be reduced.