A washing machine which prevents wrinkling of laundry in washing, rinsing, and dehydrating operations, and a method for controlling the same. The method includes determining whether a wrinkle preventing course is selected, performing a washing operation by supplying washing water to a water level designated according to an amount of the laundry disposed in the washing machine, when it is determined that the wrinkle preventing course is selected, and measuring a time of the washing operation, and additionally supplying the washing water at a designated time before the washing of the laundry is completed.