A filter assembly for a washing machine is provided which uses a simple structure to separate dirt and/or particles from washing water using. The filter assembly includes a filter case with an inlet and an outlet each positioned along its circumference, and an opening within the filler case which allows for communication between the inlet and outlet. A filter is provided in the filter case, the filter having a plate disposed in front of the opening to prevent particles from passing through the opening. Rather, the heavy particles are gathered in a central area of the filter by a centrifugal force generated by the water flowing in the filter case.