Abstract: A membrane filter press comprises a plurality of one piece plastic base plates having on opposite sides recesses each bounded by a lower inner peripheral portion surrounded by a higher outer peripheral portion. In the lower inner peripheral portion of the base plate there is a circumferential groove. On each side of the base plate there is a membrane of elastomeric material. The membrane is planar in unstressed condition and has a marginal portion seated on the lower inner peripheral portion of the base plate. A rib on the membrane is received in the circumferential groove of the base plate. An inlet for a suspension to be filtered provides inlet passages into spaces between filter cloths of adjacent filter units. At a position for filtrate outlet, passages in the membrane and the base plate connect with a filtrate outlet opening.