The invention relates to a seat cleaning-capable double-seat valve (1) with two serially arranged closing elements (3, 4), moveable relative to each other and designed as slide pistons, which border both in the closed and open position of the double seat valve (1) a leakage cavity (9), which is connected with the surroundings of the double-seat valve (1) via a tubular shaft (4b/4c) arranged on a low-lying (with respect to a vertical normal position of the double-seat valve (1)), second closing element (4), in which a drainage hole (4d) is arranged. The second, independently driven closing element (4) is thereby designed larger than the first, independently driven closing element (3) so that, as a result, the double-seat valve (1) opens downward and the drainage of the leakage cavity (9) also takes place downward.