A device for ventilating chairs comprises an air-permeable covering portion (13, 14) which is applied over the filling (7) of the chair, an insert (15; 59) located between the covering portion and the filling and a suction device (26) which through a system of suction openings in the covering (57, 60) and the insert (40, 56) evacuates the ventilating air. According to the invention the insert (15) is joined with the covering (9) of the chair to an integrated unit, which is tightened against the filling (7), and from the insert (15) there extends a duct connection (40, 25) tightly separated from the filling, which leads the air to the suction device.