Disclosed are a washing machine that performs a washing course by heating wash water and a control method thereof. The method may include selecting a certain washing course from a plurality of washing courses, sensing an amount of laundry received in an inner tub and determining a wash water level required for main washing of the determined amount of laundry, supplying wash water up to a wash water level for generation of steam such that a portion of the laundry is moistened, the wash water level being higher than a bottom surface of the inner tub and lower than the wash water level for main washing, heating the wash water to a first set temperature and driving a wash water heater to generate steam from the wash water, supplying additional wash water up to the wash water level for main washing, and performing a main washing cycle.