The invention relates to a device for aeration and ventilation of a fuel system of a motor vehicle, with a pipe union for connecting the device to the fuel system, the pipe union being connected via a connecting element to a three-way valve via which the pipe union can be fluid-connected alternately to an air inlet opening or an air outlet opening of the device. Furthermore, there is a filter element which is located in the flow path between the air inlet opening and the three-way valve. The filter element, the three-way valve, and the connecting element are accommodated in a common housing. An especially compact and space-saving device is devised by the integration of the three-way valve, connecting element, and filter element into one unit.