A device for the suction filtration of fluids, such as urea solutions for exhaust gas after-treatment systems, has a tank (2) storing the fluid, and a filter element (34) arranged in the tank and provided with a filter medium (32) separating the tank contents from a clean-side inner filter cavity (20). The filter cavity extends from the bottom (10) of the tank (2) to a filling level height (28) and corresponds to a part of the filling volume of the tank (2). On the filter cavity (20), a suction connection (22) discharges the cleaned fluid by a suction pressure corresponding to a system operating pressure. The filter element (34) is provided with a filter medium (32), which is air-impermeable if suction pressures are within the range of a low system operating pressure.